5.5.1 Release

Technically unused in VV for now, but may also replace some in-code sound mappings later

.github/workflows/build.yml

@@ -1,6 +1,6 @@
 name: Java CI with Gradle
 
-on: [push, pull_request]
+on: [push, pull_request, workflow_dispatch]
 
 jobs:
   build:
@@ -11,13 +11,13 @@ jobs:
 
     steps:
     - name: Checkout Repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v5
       with:
         persist-credentials: false
     - name: Set up Gradle
-      uses: gradle/actions/setup-gradle@v4
+      uses: gradle/actions/setup-gradle@v5
     - name: Set up JDK 17
-      uses: actions/setup-java@v4
+      uses: actions/setup-java@v5
       with:
         distribution: 'temurin'
         java-version: 17
@@ -26,7 +26,7 @@ jobs:
       run: ./gradlew build
     - name: Upload Artifacts to GitHub
       # Only upload on the preview repository as there is no CI job for it.
-      if: ${{ github.repository == 'ViaVersionDev' && github.ref_name == 'preview' }}
+      if: ${{ github.repository == 'ViaVersion/ViaVersionDev' && github.ref_name == 'preview' }}
       uses: actions/upload-artifact@v4
       with:
         name: Artifacts

.github/workflows/publish.yml

@@ -4,6 +4,7 @@ on:
     branches:
       - master
       - dev
+  workflow_dispatch:
 
 jobs:
   publish:
@@ -11,19 +12,26 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
+        uses: gradle/actions/setup-gradle@v5
       - name: Set up JDK 17
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
           java-version: 17
           check-latest: true
-      - name: Publish
+      - name: Build
+        run: ./gradlew build
+      - name: Publish to Hangar
         env:
           HANGAR_TOKEN: ${{ secrets.HANGAR_TOKEN }}
+        run: ./gradlew publishAllPublicationsToHangar --stacktrace
+        continue-on-error: true
+      - name: Publish to Modrinth
+        env:
           MODRINTH_TOKEN: ${{ secrets.MODRINTH_TOKEN }}
-        run: ./gradlew build modrinth publishAllPublicationsToHangar --stacktrace
+        run: ./gradlew modrinth --stacktrace
+        continue-on-error: true

.github/workflows/update-gradle-wrapper.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           persist-credentials: false
       - name: Update Gradle Wrapper

.gitignore

@@ -1,115 +1,36 @@
-### Java files ###
-*.class
+# Gradle
 
-# Package Files
-#*.jar
-*.war
-*.ear
+.gradle/
+build/
+out/
+classes/
+.kotlin/
 
-# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
-hs_err_pid*
+# Eclipse
 
+*.launch
 
+# Idea
 
-### Intellij ###
-# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm
-# Ignore project files
-*.iml
-
-# Ignore IDEA directory
-.idea/*
+.idea/
 !.idea/copyright/*
 !.idea/scopes/*
-
-# Include the project's dictionary
-!.idea/dictionaries/
-!.idea/dictionaries/*
-
-# File-based project format:
+*.iml
 *.ipr
 *.iws
 
-### Plugin-specific files: ###
-# IntelliJ
-/out/
+# VSCode
 
-# mpeltonen/sbt-idea plugin
-.idea_modules/
-
-# JIRA plugin
-atlassian-ide-plugin.xml
-
-# Crashlytics plugin (for Android Studio and IntelliJ)
-com_crashlytics_export_strings.xml
-crashlytics.properties
-crashlytics-build.properties
-
-
-
-### Eclipse ###
-*.pydevproject
-.metadata
-.gradle
-bin/
-tmp/
-*.tmp
-*.bak
-*.swp
-*~.nib
-local.properties
 .settings/
-.loadpath
-
-# Eclipse Core
+.vscode/
+bin/
+.classpath
 .project
 
-# External tool builders
-.externalToolBuilders/
+# macOS
 
-# Locally stored "Eclipse launch configurations"
-*.launch
-
-# CDT-specific
-.cproject
-
-# JDT-specific (Eclipse Java Development Tools)
-.classpath
-
-# PDT-specific
-.buildpath
-
-# sbteclipse plugin
-.target
-
-# TeXlipse plugin
-.texlipse
-
-
-
-### Maven ###
-target/
-pom.xml.tag
-pom.xml.releaseBackup
-pom.xml.versionsBackup
-pom.xml.next
-release.properties
-dependency-reduced-pom.xml
-buildNumber.properties
-
-
-
-### NetBeans ###
-nbproject/private/
-build/
-nbbuild/
-dist/
-nbdist/
-nbactions.xml
-nb-configuration.xml
-.nb-gradle/
-
-### MacOS ###
 .DS_Store
 
-### Run Folder (ViaProxy) ###
-common/run/
+# Misc
+
+run/

README.md

@@ -8,7 +8,7 @@
 it works on any platform you can think of.**
 
 The base ViaVersion jar runs on Paper and Velocity. We also have projects integrating ViaVersion to run
-on Fabric, Forge, Bungee, Sponge, or as a standalone proxy to join from basically any client version on
+on Fabric, Forge, Sponge, or as a standalone proxy to join from basically any client version on
 any server version from the past decade. **See [HERE](https://viaversion.com) for an overview of the different Via\* projects.**
 
 Note that ViaVersion will be able to **run best on either Paper servers or through [ViaFabricPlus](https://github.com/ViaVersion/ViaFabricPlus?tab=readme-ov-file#viafabricplus)** due to having
@@ -16,9 +16,9 @@ direct access to client/server state and more extensive API.
 
 Supported Versions:
 
-![Table (https://i.imgur.com/zrQTcf0.png)](https://i.imgur.com/zrQTcf0.png)
+![Table (https://ci.viaversion.com/userContent/images/T.png)](https://ci.viaversion.com/userContent/images/T.png)
 
-**User Docs:** https://docs.viaversion.com/display/VIAVERSION/
+**User Docs:** https://docs.viaversion.com
 
 Snapshot support
 --------
@@ -87,12 +87,10 @@ of the `build/libs` directory.
 
 You need JDK 17 or newer to build ViaVersion.
 
-
 Mapping Files
 --------------
 Mapping files are generated and managed in our [Mappings repository](https://github.com/ViaVersion/Mappings). The generated mapping output is stored [here](./common/src/main/resources/assets/viaversion).
 
-
 Resources
 --------
 

SECURITY.md

@@ -0,0 +1,10 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+If you discover a **security vulnerability**, please **do not** open a public issue. Instead, use one of the following **confidential contact methods**:
+
+* **Email:** [security@viaversion.com](mailto:security@viaversion.com)
+* **Discord:** Join our [Discord server](https://discord.gg/viaversion) and visit the [#exploit-report](https://discord.com/channels/316206679014244363/1388847764137316485) channel for further instructions.
+
+If your issue is **not security-related** (e.g., bug reports, feature requests, or usage questions), please use the [GitHub Issues page](https://github.com/ViaVersion/ViaVersion/issues) or contact us via the [Discord server](https://discord.gg/viaversion).

api/build.gradle.kts

@@ -29,7 +29,11 @@ dependencies {
     api(libs.snakeYaml)
 
     compileOnlyApi(libs.netty)
-    compileOnlyApi(libs.guava)
+    compileOnlyApi(libs.guava) {
+        exclude("com.google.errorprone", "error_prone_annotations")
+        exclude("org.jspecify", "jspecify")
+        exclude("com.google.j2objc", "j2objc-annotations")
+    }
     compileOnlyApi(libs.checkerQual)
 }
 

api/src/main/java-templates/com/viaversion/viaversion/util/VersionInfo.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2024 ViaVersion and contributors
+ * Copyright (C) 2016-2025 ViaVersion and contributors
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal

api/src/main/java/com/viaversion/viaversion/api/ViaAPI.java

@@ -114,7 +114,8 @@ public interface ViaAPI<T> {
     ProtocolVersion getPlayerProtocolVersion(UUID uuid);
 
     /**
-     * Returns whether Via injected into this player connection.
+     * Returns whether Via injected into this player connection. Note that this method may not work on
+     * clientside implementations and is generally not recommended to be used. Use {@link ConnectionManager} instead.
      *
      * @param uuid uuid of the player
      * @return whether Via has a cached a UserConnection for this player
@@ -122,7 +123,8 @@ public interface ViaAPI<T> {
     boolean isInjected(UUID uuid);
 
     /**
-     * Returns the Via injected UserConnection if present.
+     * Returns the injected UserConnection if present. Note that this method may not work on
+     * clientside implementations and is generally not recommended to be used. Use {@link ConnectionManager} instead.
      *
      * @param uuid uuid of the player
      * @return user connection if present

api/src/main/java/com/viaversion/viaversion/api/command/ViaSubCommand.java

@@ -66,7 +66,7 @@ public interface ViaSubCommand {
      *
      * @param sender Command sender
      * @param args   Arguments
-     * @return commands executed succesfully if false, show usage
+     * @return commands executed successfully if false, show usage
      */
     boolean execute(ViaCommandSender sender, String[] args);
 

api/src/main/java/com/viaversion/viaversion/api/command/ViaVersionCommand.java

@@ -30,7 +30,7 @@ public interface ViaVersionCommand {
      * Register your own subcommand inside ViaVersion
      *
      * @param command Your own SubCommand instance to handle it.
-     * @throws IllegalArgumentException throws an exception when the subcommand already exists or if it's not valid, example: spacee
+     * @throws IllegalArgumentException throws an exception when the subcommand already exists or if it's not valid, example: space
      */
     void registerSubCommand(ViaSubCommand command);
 

api/src/main/java/com/viaversion/viaversion/api/configuration/RateLimitConfig.java

@@ -0,0 +1,27 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.configuration;
+
+public record RateLimitConfig(boolean enabled, int maxRate, String maxRateKickMessage, int warningRate, int maxWarnings,
+                              long trackingPeriodNanos, String warningKickMessage, String ratePlaceholder) {
+}

api/src/main/java/com/viaversion/viaversion/api/configuration/ViaVersionConfig.java

@@ -147,6 +147,7 @@ public interface ViaVersionConfig extends Config {
      *
      * @return The number of packets a client can send per second.
      */
+    @Deprecated(forRemoval = true)
     int getMaxPPS();
 
     /**
@@ -154,6 +155,7 @@ public interface ViaVersionConfig extends Config {
      *
      * @return Kick message, with colour codes using '&'
      */
+    @Deprecated(forRemoval = true)
     String getMaxPPSKickMessage();
 
     /**
@@ -161,6 +163,7 @@ public interface ViaVersionConfig extends Config {
      *
      * @return Time in seconds that should be tracked for warnings
      */
+    @Deprecated(forRemoval = true)
     int getTrackingPeriod();
 
     /**
@@ -168,6 +171,7 @@ public interface ViaVersionConfig extends Config {
      *
      * @return The number of packets per second to count as a warning.
      */
+    @Deprecated(forRemoval = true)
     int getWarningPPS();
 
     /**
@@ -175,6 +179,7 @@ public interface ViaVersionConfig extends Config {
      *
      * @return The number of packets a client can send per second.
      */
+    @Deprecated(forRemoval = true)
     int getMaxWarnings();
 
     /**
@@ -182,8 +187,13 @@ public interface ViaVersionConfig extends Config {
      *
      * @return Kick message, with colour codes using '&'
      */
+    @Deprecated(forRemoval = true)
     String getMaxWarningsKickMessage();
 
+    RateLimitConfig getPacketTrackerConfig();
+
+    RateLimitConfig getPacketSizeTrackerConfig();
+
     /**
      * Send supported versions in the status response packet
      *
@@ -233,13 +243,6 @@ public interface ViaVersionConfig extends Config {
      */
     boolean isChunkBorderFix();
 
-    /**
-     * Should we fix nbt array's in json chat messages for 1.12 clients
-     *
-     * @return true if enabled
-     */
-    boolean is1_12NBTArrayFix();
-
     /**
      * Should we make team colours based on the last colour in team prefix
      *
@@ -270,6 +273,8 @@ public interface ViaVersionConfig extends Config {
      */
     String getBlockedDisconnectMsg();
 
+    boolean logBlockedJoins();
+
     /**
      * Get the message sent to players being kicked on reload.
      * Players are kicked to stop the server crashing
@@ -285,6 +290,13 @@ public interface ViaVersionConfig extends Config {
      */
     boolean isSuppressConversionWarnings();
 
+    /**
+     * Should we hide errors that occur when trying to convert text components?
+     *
+     * @return true if enabled
+     */
+    boolean isSuppressTextComponentConversionWarnings();
+
     /**
      * Should we disable the 1.13 auto-complete feature to stop spam kicks? (for any server lower than 1.13)
      *
@@ -478,4 +490,12 @@ public interface ViaVersionConfig extends Config {
      * @return true if enabled
      */
     boolean fix1_21PlacementRotation();
+
+    /**
+     * If enabled, cancel swing packets sent while having an inventory opened on 1.15.2 and below servers.
+     * This can cause false positives with anti-cheat plugins.
+     *
+     * @return true if enabled
+     */
+    boolean cancelSwingInInventory();
 }

api/src/main/java/com/viaversion/viaversion/api/connection/ConnectionManager.java

@@ -28,51 +28,81 @@ import java.util.UUID;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
- * Handles injected UserConnections
+ * Handles injected UserConnections.
+ * Check {@link UserConnection#isServerSide()} and {@link UserConnection#isClientSide()} to determine the connection type.
  */
 public interface ConnectionManager {
 
     /**
-     * Returns if Via injected into this player connection.
+     * Returns if Via has injected. See above for the connection types.
      *
-     * @param playerId player uuid
+     * @param uuid player uuid
      * @return true if the player is handled by Via
      */
-    boolean isClientConnected(UUID playerId);
+    boolean hasServerConnection(UUID uuid);
 
-    /**
-     * Frontend connections will have the UUID stored. Override this if your platform isn't always frontend.
-     * UUIDs can't be duplicate between frontend connections.
-     *
-     * @return true if the user is a frontend connection
-     */
-    default boolean isFrontEnd(UserConnection connection) {
-        return !connection.isClientSide();
+    @Deprecated
+    default boolean isClientConnected(UUID uuid) {
+        return hasServerConnection(uuid);
     }
 
     /**
-     * Returns the frontend UserConnection from the player connected to this proxy server
-     * Returns null when there isn't a server or connection was not found
-     * When ViaVersion is reloaded, this method may not return some players.
-     * <p>
-     * Note that connections are removed as soon as their channel is closed,
-     * so avoid using this method during player quits for example.
+     * Returns if Via has injected. See above for the connection types.
      *
-     * @return frontend UserConnection of the player connected to this proxy server
+     * @param uuid player uuid
+     * @return true if the player is handled by Via
      */
-    @Nullable UserConnection getConnectedClient(UUID clientIdentifier);
+    boolean hasClientConnection(UUID uuid);
 
     /**
-     * Returns the UUID from the frontend connection to this proxy server
-     * Returns null when there isn't a server or this connection isn't frontend, or it doesn't have an id
+     * Returns the server UserConnection. See above for the connection types.
      * When ViaVersion is reloaded, this method may not return some players.
      * <p>
      * Note that connections are removed as soon as their channel is closed,
      * so avoid using this method during player quits for example.
      *
-     * @return UUID of the frontend connection to this proxy server
+     * @return server UserConnection of the player or null
      */
-    @Nullable UUID getConnectedClientId(UserConnection connection);
+    @Nullable
+    UserConnection getServerConnection(UUID uuid);
+
+    @Deprecated
+    @Nullable default UserConnection getConnectedClient(UUID uuid) {
+        return getServerConnection(uuid);
+    }
+
+    /**
+     * Returns the client UserConnection. See above for the connection types.
+     * When ViaVersion is reloaded, this method may not return some players.
+     * <p>
+     * Note that connections are removed as soon as their channel is closed,
+     * so avoid using this method during player quits for example.
+     *
+     * @return client UserConnection of the player or null
+     */
+    @Nullable
+    UserConnection getClientConnection(UUID uuid);
+
+    /**
+     * Returns a map containing the UUIDs and server UserConnections
+     * When ViaVersion is reloaded, this method may not return some players.
+     *
+     * @return map containing the UUIDs and frontend UserConnections
+     */
+    Map<UUID, UserConnection> getServerConnections();
+
+    @Deprecated
+    default Map<UUID, UserConnection> getConnectedClients() {
+        return getServerConnections();
+    }
+
+    /**
+     * Returns a map containing the UUIDs and client UserConnections
+     * When ViaVersion is reloaded, this method may not return some players.
+     *
+     * @return map containing the UUIDs and client UserConnections
+     */
+    Map<UUID, UserConnection> getClientConnections();
 
     /**
      * Returns all UserConnections which are registered
@@ -84,15 +114,6 @@ public interface ConnectionManager {
      */
     Set<UserConnection> getConnections();
 
-    /**
-     * Returns a map containing the UUIDs and frontend UserConnections from players connected to this proxy server
-     * Returns empty list when there isn't a server
-     * When ViaVersion is reloaded, this method may not return some players.
-     *
-     * @return map containing the UUIDs and frontend UserConnections from players connected to this proxy server
-     */
-    Map<UUID, UserConnection> getConnectedClients();
-
     void onLoginSuccess(UserConnection connection);
 
     void onDisconnect(UserConnection connection);

api/src/main/java/com/viaversion/viaversion/api/connection/StorableObject.java

@@ -30,15 +30,6 @@ package com.viaversion.viaversion.api.connection;
  */
 public interface StorableObject {
 
-    /**
-     * Returns whether the object should be uncached on a server switch.
-     *
-     * @return whether the object should be uncached on a server switch
-     */
-    default boolean clearOnServerSwitch() {
-        return true;
-    }
-
     default void onRemove() {
     }
 }

api/src/main/java/com/viaversion/viaversion/api/connection/UserConnection.java

@@ -24,6 +24,7 @@ package com.viaversion.viaversion.api.connection;
 
 import com.viaversion.viaversion.api.configuration.ViaVersionConfig;
 import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.data.item.ItemHasher;
 import com.viaversion.viaversion.api.minecraft.ClientWorld;
 import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.packet.PacketTracker;
@@ -99,6 +100,23 @@ public interface UserConnection {
      */
     void addEntityTracker(Class<? extends Protocol> protocolClass, EntityTracker tracker);
 
+    /**
+     * Adds an item hasher to the user connection.
+     *
+     * @param protocolClass protocol class
+     * @param itemHasher   item hasher
+     */
+    void addItemHasher(Class<? extends Protocol> protocolClass, ItemHasher itemHasher);
+
+    /**
+     * Returns the item hasher by the given protocol class if present.
+     *
+     * @param protocolClass protocol class
+     * @param <T>           item hasher type
+     * @return item hasher if present
+     */
+    @Nullable <T extends ItemHasher> T getItemHasher(Class<? extends Protocol> protocolClass);
+
     /**
      * Returns the client world by the given protocol class if present.
      *
@@ -121,17 +139,7 @@ public interface UserConnection {
     /**
      * Clear stored objects, entity trackers and client worlds.
      */
-    default void clearStoredObjects() {
-        clearStoredObjects(false);
-    }
-
-    /**
-     * Clear stored objects, entity trackers and client worlds.
-     * If cleared for a proxy server switch, some stored objects and tracker data will be retained.
-     *
-     * @param isServerSwitch whether the clear is due to a server switch
-     */
-    void clearStoredObjects(boolean isServerSwitch);
+    void clearStoredObjects();
 
     /**
      * Sends a raw packet to the connection on the current thread.
@@ -186,9 +194,15 @@ public interface UserConnection {
     /**
      * Monitors serverbound packets and returns whether a packet can/should be processed.
      *
+     * @param bytes the number of bytes in the packet
      * @return false if this packet should be cancelled
      */
-    boolean checkServerboundPacket();
+    boolean checkServerboundPacket(int bytes);
+
+    @Deprecated(forRemoval = true)
+    default boolean checkServerboundPacket() {
+        return checkServerboundPacket(0);
+    }
 
     /**
      * Monitors clientbound packets and returns whether a packet can/should be processed.
@@ -201,6 +215,11 @@ public interface UserConnection {
      * @see #checkClientboundPacket()
      * @see #checkServerboundPacket()
      */
+    default boolean checkIncomingPacket(final int bytes) {
+        return isClientSide() ? checkClientboundPacket() : checkServerboundPacket(bytes);
+    }
+
+    @Deprecated(forRemoval = true)
     default boolean checkIncomingPacket() {
         return isClientSide() ? checkClientboundPacket() : checkServerboundPacket();
     }
@@ -319,23 +338,35 @@ public interface UserConnection {
     void setPendingDisconnect(boolean pendingDisconnect);
 
     /**
-     * Returns whether this is a client-side connection.
-     * This is a mod integrated into the client itself, or for example a backend Velocity connection.
+     * Returns whether this is a backend connection.
+     * This is a mod integrated into the client, or for example a backend Velocity connection.
      *
-     * @return whether this is a client-side connection
+     * @return whether this is a backend connection
      */
     boolean isClientSide();
 
+    /**
+     * Returns whether this is a frontend connection.
+     * This is a plugin integrated into the server, or for example a frontend Velocity connection.
+     *
+     * @return whether this is a frontend connection
+     */
+    default boolean isServerSide() {
+        return !isClientSide();
+    }
+
     /**
      * Returns whether {@link ViaVersionConfig#blockedProtocolVersions()} should be checked for this connection.
      *
      * @return whether blocked protocols should be applied
      */
-    boolean shouldApplyBlockProtocol();
+    default boolean shouldApplyBlockProtocol() {
+        return isServerSide();
+    }
 
     /**
      * Returns a newly generated uuid that will let a packet be passed through without
-     * transformig its contents if used together with {@link PacketWrapper#PASSTHROUGH_ID}.
+     * transforming its contents if used together with {@link PacketWrapper#PASSTHROUGH_ID}.
      *
      * @return generated passthrough token
      */

api/src/main/java/com/viaversion/viaversion/api/data/MappingData.java

@@ -24,6 +24,7 @@ package com.viaversion.viaversion.api.data;
 
 import com.viaversion.viaversion.api.minecraft.RegistryType;
 import com.viaversion.viaversion.api.minecraft.TagData;
+import it.unimi.dsi.fastutil.ints.IntSet;
 import java.util.List;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
@@ -140,12 +141,14 @@ public interface MappingData {
 
     @Nullable Mappings getBlockMappings();
 
-    @Nullable Mappings getBlockEntityMappings();
+    @Nullable FullMappings getFullBlockMappings();
 
     @Nullable Mappings getBlockStateMappings();
 
     @Nullable Mappings getSoundMappings();
 
+    @Nullable FullMappings getFullSoundMappings();
+
     @Nullable Mappings getStatisticsMappings();
 
     @Nullable Mappings getMenuMappings();
@@ -154,6 +157,8 @@ public interface MappingData {
 
     @Nullable Mappings getPaintingMappings();
 
+    @Nullable FullMappings getBlockEntityMappings();
+
     @Nullable FullMappings getAttributeMappings();
 
     @Nullable FullMappings getEntityMappings();
@@ -163,4 +168,26 @@ public interface MappingData {
     @Nullable FullMappings getRecipeSerializerMappings();
 
     @Nullable FullMappings getDataComponentSerializerMappings();
+
+    default @Nullable FullMappings getFullMappings(final MappingType mappingType) {
+        return switch (mappingType) {
+            case ITEM -> getFullItemMappings();
+            case SOUND -> getFullSoundMappings();
+            case ENTITY -> getEntityMappings();
+        };
+    }
+
+    /**
+     * Set of block (not block state) ids that had their base type or properties changed.
+     *
+     * @return set of changed block ids, or null if not tracked/none are present
+     */
+    @Nullable IntSet changedBlocks();
+
+    /**
+     * Type of mappings. Currently only relevant for ops writing of generic holder classes and expanded when needed.
+     */
+    enum MappingType {
+        ITEM, SOUND, ENTITY
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/data/MappingDataBase.java

@@ -28,6 +28,8 @@ import com.viaversion.nbt.tag.Tag;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.minecraft.RegistryType;
 import com.viaversion.viaversion.api.minecraft.TagData;
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
+import it.unimi.dsi.fastutil.ints.IntSet;
 import java.util.ArrayList;
 import java.util.EnumMap;
 import java.util.List;
@@ -44,17 +46,21 @@ public class MappingDataBase implements MappingData {
     protected FullMappings recipeSerializerMappings;
     protected FullMappings itemDataSerializerMappings;
     protected FullMappings attributeMappings;
+    protected FullMappings blockEntityMappings;
     protected ParticleMappings particleMappings;
     protected BiMappings itemMappings;
     protected BiMappings blockMappings;
     protected Mappings blockStateMappings;
-    protected Mappings blockEntityMappings;
     protected Mappings soundMappings;
     protected Mappings statisticsMappings;
     protected Mappings enchantmentMappings;
     protected Mappings paintingMappings;
     protected Mappings menuMappings;
     protected Map<RegistryType, List<TagData>> tags;
+    /**
+     * Set of block ids that have had type or property changes.
+     */
+    protected IntSet changedBlocks;
 
     public MappingDataBase(final String unmappedVersion, final String mappedVersion) {
         this.unmappedVersion = unmappedVersion;
@@ -68,10 +74,7 @@ public class MappingDataBase implements MappingData {
         }
 
         final CompoundTag data = readMappingsFile("mappings-" + unmappedVersion + "to" + mappedVersion + ".nbt");
-        blockMappings = loadBiMappings(data, "blocks");
         blockStateMappings = loadMappings(data, "blockstates");
-        blockEntityMappings = loadMappings(data, "blockentities");
-        soundMappings = loadMappings(data, "sounds");
         statisticsMappings = loadMappings(data, "statistics");
         menuMappings = loadMappings(data, "menus");
         enchantmentMappings = loadMappings(data, "enchantments");
@@ -80,12 +83,16 @@ public class MappingDataBase implements MappingData {
         final CompoundTag unmappedIdentifierData = readUnmappedIdentifiersFile("identifiers-" + unmappedVersion + ".nbt");
         final CompoundTag mappedIdentifierData = readMappedIdentifiersFile("identifiers-" + mappedVersion + ".nbt");
         if (unmappedIdentifierData != null && mappedIdentifierData != null) {
-            itemMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "items");
+            itemMappings = loadFullOrBiMappings(data, unmappedIdentifierData, mappedIdentifierData, "items");
+            blockMappings = loadFullOrBiMappings(data, unmappedIdentifierData, mappedIdentifierData, "blocks");
+            soundMappings = loadFullOrBiMappings(data, unmappedIdentifierData, mappedIdentifierData, "sounds");
+
             entityMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "entities");
             argumentTypeMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "argumenttypes");
             recipeSerializerMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "recipe_serializers");
             itemDataSerializerMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "data_component_type");
             attributeMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "attributes");
+            blockEntityMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "blockentities");
 
             final List<String> unmappedParticles = identifiersFromGlobalIds(unmappedIdentifierData, "particles");
             final List<String> mappedParticles = identifiersFromGlobalIds(mappedIdentifierData, "particles");
@@ -99,6 +106,8 @@ public class MappingDataBase implements MappingData {
         } else {
             // Might not have identifiers in older versions
             itemMappings = loadBiMappings(data, "items");
+            blockMappings = loadBiMappings(data, "blocks");
+            soundMappings = loadMappings(data, "sounds");
         }
 
         final CompoundTag tagsTag = data.getCompoundTag("tags");
@@ -109,6 +118,11 @@ public class MappingDataBase implements MappingData {
             loadTags(RegistryType.ENTITY, tagsTag);
         }
 
+        final IntArrayTag changedBlocks = data.getIntArrayTag("changed_blocks");
+        if (changedBlocks != null) {
+            this.changedBlocks = new IntOpenHashSet(changedBlocks.getValue());
+        }
+
         loadExtras(data);
     }
 
@@ -132,6 +146,11 @@ public class MappingDataBase implements MappingData {
         return MappingDataLoader.INSTANCE.loadMappings(data, key);
     }
 
+    protected @Nullable BiMappings loadFullOrBiMappings(final CompoundTag data, final CompoundTag unmappedIdentifiersTag, final CompoundTag mappedIdentifiersTag, final String key) {
+        final FullMappings mappings = loadFullMappings(data, unmappedIdentifiersTag, mappedIdentifiersTag, key);
+        return mappings != null ? mappings : loadBiMappings(data, key);
+    }
+
     protected @Nullable FullMappings loadFullMappings(final CompoundTag data, final CompoundTag unmappedIdentifiersTag, final CompoundTag mappedIdentifiersTag, final String key) {
         if (!unmappedIdentifiersTag.contains(key) || !mappedIdentifiersTag.contains(key)) {
             return null;
@@ -208,8 +227,8 @@ public class MappingDataBase implements MappingData {
     }
 
     @Override
-    public int getOldSoundId(final int i) {
-        return soundMappings.getNewIdOrDefault(i, 0);
+    public int getOldSoundId(final int id) {
+        return soundMappings.inverse().getNewIdOrDefault(id, 0);
     }
 
     @Override
@@ -224,8 +243,8 @@ public class MappingDataBase implements MappingData {
 
     @Override
     public @Nullable FullMappings getFullItemMappings() {
-        if (itemMappings instanceof FullMappings) {
-            return (FullMappings) itemMappings;
+        if (itemMappings instanceof FullMappings fullItemMappings) {
+            return fullItemMappings;
         }
         return null;
     }
@@ -241,7 +260,15 @@ public class MappingDataBase implements MappingData {
     }
 
     @Override
-    public @Nullable Mappings getBlockEntityMappings() {
+    public @Nullable FullMappings getFullBlockMappings() {
+        if (blockMappings instanceof FullMappings fullBlockMappings) {
+            return fullBlockMappings;
+        }
+        return null;
+    }
+
+    @Override
+    public @Nullable FullMappings getBlockEntityMappings() {
         return blockEntityMappings;
     }
 
@@ -255,6 +282,14 @@ public class MappingDataBase implements MappingData {
         return soundMappings;
     }
 
+    @Override
+    public @Nullable FullMappings getFullSoundMappings() {
+        if (soundMappings instanceof FullMappings fullSoundMappings) {
+            return fullSoundMappings;
+        }
+        return null;
+    }
+
     @Override
     public @Nullable Mappings getStatisticsMappings() {
         return statisticsMappings;
@@ -300,6 +335,11 @@ public class MappingDataBase implements MappingData {
         return recipeSerializerMappings;
     }
 
+    @Override
+    public @Nullable IntSet changedBlocks() {
+        return changedBlocks;
+    }
+
     protected Logger getLogger() {
         return Via.getPlatform().getLogger();
     }

api/src/main/java/com/viaversion/viaversion/api/data/MappingDataLoader.java

@@ -210,7 +210,7 @@ public class MappingDataLoader {
             return null;
         }
 
-        final int mappedSize = tag.getIntTag("mappedSize").asInt();
+        final int mappedSize = tag.getInt("mappedSize", -1);
         final byte strategy = tag.getByteTag("id").asByte();
         final V mappings;
         if (strategy == DIRECT_ID) {

api/src/main/java/com/viaversion/viaversion/api/data/entity/EntityTracker.java

@@ -82,6 +82,11 @@ public interface EntityTracker {
      */
     void clearEntities();
 
+    /**
+     * Clears all stored data, including entity types, entity data and client entity id.
+     */
+    void clear();
+
     /**
      * Returns the stored entity data if an entity with the id is tracked, else null.
      * If no data has been initialized yet, it will be done and returned by this method.
@@ -123,6 +128,20 @@ public interface EntityTracker {
      */
     void setClientEntityId(int clientEntityId);
 
+    /**
+     * Returns whether the client player has the "insta build" ability, usually from creative mode.
+     *
+     * @return whether the client player can insta build
+     */
+    boolean canInstaBuild();
+
+    /**
+     * Sets whether the client player has the "insta build" ability, usually from creative mode.
+     *
+     * @param instaBuild whether the client player can insta build
+     */
+    void setInstaBuild(boolean instaBuild);
+
     /**
      * Returns the current world section height (block height / 16).
      * This is always 16 for sub 1.17 worlds.
@@ -166,6 +185,20 @@ public interface EntityTracker {
      */
     void setCurrentWorld(String currentWorld);
 
+    /**
+     * Returns the id of the current dimension, or -1 if unset (i.e. before 1.20.5).
+     *
+     * @return id of the current dimension, or -1 if unset
+     */
+    int currentDimensionId();
+
+    /**
+     * Sets the id of the current dimension.
+     *
+     * @param currentDimensionId id of the current dimension
+     */
+    void setCurrentDimensionId(int currentDimensionId);
+
     int biomesSent();
 
     void setBiomesSent(int biomesSent);

api/src/main/java/com/viaversion/viaversion/api/data/item/ItemHasher.java

@@ -0,0 +1,51 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.data.item;
+
+import java.util.List;
+
+/**
+ * Used for converting items to hashed items and caching them for later use during serverbound packets.
+ * <p>
+ * Most of this stays in the internal module given non-permanent, imperfect caching as well as missing converters.
+ */
+public interface ItemHasher {
+
+    /**
+     * Returns whether this connection is currently processing a clientbound player inventory packet.
+     * <p>
+     * Used for checking when it is necessary to track/process item data hashes.
+     *
+     * @return true if processing a clientbound inventory packet, false otherwise
+     */
+    boolean isProcessingClientboundInventoryPacket();
+
+    void setProcessingClientboundInventoryPacket(boolean processingClientboundInventoryPacket);
+
+    /**
+     * Sets the enchantment registry for this connection.
+     *
+     * @param enchantments list of enchantment identifiers
+     */
+    void setEnchantments(List<String> enchantments);
+}

api/src/main/java/com/viaversion/viaversion/api/debug/DebugHandler.java

@@ -22,7 +22,6 @@
  */
 package com.viaversion.viaversion.api.debug;
 
-import com.google.common.annotations.Beta;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.protocol.packet.Direction;
 import com.viaversion.viaversion.api.protocol.packet.PacketType;
@@ -50,7 +49,6 @@ public interface DebugHandler {
      *
      * @param packetTypeName packet type name
      */
-    @Beta
     void addPacketTypeNameToLog(String packetTypeName);
 
     /**
@@ -59,7 +57,6 @@ public interface DebugHandler {
      *
      * @param packetType packet type
      */
-    @Beta
     void addPacketTypeToLog(PacketType packetType);
 
     /**
@@ -67,22 +64,44 @@ public interface DebugHandler {
      *
      * @param packetTypeName packet type name
      */
-    @Beta
     boolean removePacketTypeNameToLog(String packetTypeName);
 
     /**
      * Resets packet type filters.
      */
-    @Beta
     void clearPacketTypesToLog();
 
+    /**
+     * Sets whether packets should be logged before and after being transformed.
+     *
+     * @param logPacketTransform whether packets should be logged
+     */
+    default void setLogPacketTransform(boolean logPacketTransform) {
+        setLogPrePacketTransform(logPacketTransform);
+        setLogPostPacketTransform(logPacketTransform);
+    }
+
+    /**
+     * Returns whether packets should be logged before being transformed.
+     * Set to true by default.
+     *
+     * @return whether packets should be logged before being transformed
+     */
+    boolean logPrePacketTransform();
+
+    /**
+     * Sets whether packets should be logged before being transformed.
+     *
+     * @param logPrePacketTransform whether packets should be logged before being transformed
+     */
+    void setLogPrePacketTransform(boolean logPrePacketTransform);
+
     /**
      * Returns whether packets should be logged after being transformed.
      * Set to false by default.
      *
      * @return whether packets should be logged after being transformed
      */
-    @Beta
     boolean logPostPacketTransform();
 
     /**
@@ -90,7 +109,6 @@ public interface DebugHandler {
      *
      * @param logPostPacketTransform whether packets should be logged after being transformed
      */
-    @Beta
     void setLogPostPacketTransform(boolean logPostPacketTransform);
 
     /**
@@ -103,7 +121,6 @@ public interface DebugHandler {
      */
     boolean shouldLog(PacketWrapper wrapper, Direction direction);
 
-    @Beta
     default void enableAndLogIds(final PacketType... packetTypes) {
         setEnabled(true);
         for (final PacketType packetType : packetTypes) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/AnimalVariant.java

@@ -0,0 +1,55 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft;
+
+import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.api.type.types.misc.HolderType;
+import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/**
+ * Represents an animal variant (e.g. for cows, pigs, chickens).
+ *
+ * @param modelType model type id
+ * @param texture texture path
+ * @param biomes biomes this variant can spawn in, if limited to specific biomes
+ */
+public record AnimalVariant(int modelType, String texture, @Nullable HolderSet biomes) {
+
+    public static HolderType<AnimalVariant> TYPE = new HolderType<>() {
+        @Override
+        public AnimalVariant readDirect(final ByteBuf buffer) {
+            final int modelType = Types.VAR_INT.readPrimitive(buffer);
+            final String texture = Types.STRING.read(buffer);
+            final HolderSet biomes = Types.OPTIONAL_HOLDER_SET.read(buffer);
+            return new AnimalVariant(modelType, texture, biomes);
+        }
+
+        @Override
+        public void writeDirect(final ByteBuf buffer, final AnimalVariant variant) {
+            Types.VAR_INT.writePrimitive(buffer, variant.modelType());
+            Types.STRING.write(buffer, variant.texture());
+            Types.OPTIONAL_HOLDER_SET.write(buffer, variant.biomes());
+        }
+    };
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/BlockChangeRecord1_16_2.java

@@ -58,7 +58,7 @@ public class BlockChangeRecord1_16_2 implements BlockChangeRecord {
 
     @Override
     public short getY(int chunkSectionY) {
-        Preconditions.checkArgument(chunkSectionY >= 0, "Invalid chunkSectionY: " + chunkSectionY);
+        Preconditions.checkArgument(chunkSectionY >= 0, "Invalid chunkSectionY: %s", chunkSectionY);
         return (short) ((chunkSectionY << 4) + sectionY);
     }
 

api/src/main/java/com/viaversion/viaversion/api/minecraft/BlockFace.java

@@ -33,7 +33,6 @@ public enum BlockFace {
     TOP((byte) 0, (byte) 1, (byte) 0, EnumAxis.Y),
     BOTTOM((byte) 0, (byte) -1, (byte) 0, EnumAxis.Y);
 
-    public static final BlockFace[] HORIZONTAL = {NORTH, SOUTH, EAST, WEST};
     private static final Map<BlockFace, BlockFace> opposites = new EnumMap<>(BlockFace.class);
 
     static {

api/src/main/java/com/viaversion/viaversion/api/minecraft/EitherHolder.java

@@ -0,0 +1,82 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft;
+
+public interface EitherHolder<T> {
+
+    /**
+     * Returns a direct or indirect value holder.
+     *
+     * @param value the value
+     * @param <T>   the type of the value
+     * @return a new direct holder
+     */
+    static <T> EitherHolder<T> of(final Holder<T> value) {
+        return new EitherHolderImpl<>(value, null);
+    }
+
+    /**
+     * Returns an indirect holder via the resource key.
+     *
+     * @param key  the resource key
+     * @param <T> the type of the value
+     * @return a new holder with the given resource key
+     */
+    static <T> EitherHolder<T> of(final String key) {
+        return new EitherHolderImpl<>(null, key);
+    }
+
+    /**
+     * Returns true if this holder is backed by a direct value.
+     *
+     * @return true if the holder is direct
+     * @see #hasKey()
+     */
+    boolean hasHolder();
+
+    /**
+     * Returns true if this holder has a resource key.
+     *
+     * @return true if this holder has a resource key
+     * @see #hasHolder()
+     */
+    boolean hasKey();
+
+    /**
+     * Returns the value of this holder.
+     *
+     * @return the value of this holder
+     * @throws IllegalArgumentException if this contains a resource key instead of a holder
+     * @see #hasHolder()
+     */
+    Holder<T> holder();
+
+    /**
+     * Returns the resource key.
+     *
+     * @return the resource key
+     * @throws IllegalArgumentException if this contains a holder instead of a resource key
+     * @see #hasKey()
+     */
+    String key();
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/EitherHolderImpl.java

@@ -0,0 +1,55 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.util.EitherImpl;
+
+final class EitherHolderImpl<T> extends EitherImpl<Holder<T>, String> implements EitherHolder<T> {
+
+    EitherHolderImpl(final Holder<T> left, final String value) {
+        super(left, value);
+    }
+
+    @Override
+    public boolean hasHolder() {
+        return isLeft();
+    }
+
+    @Override
+    public boolean hasKey() {
+        return isRight();
+    }
+
+    @Override
+    public Holder<T> holder() {
+        Preconditions.checkArgument(hasHolder(), "Either does not have a holder");
+        return left();
+    }
+
+    @Override
+    public String key() {
+        Preconditions.checkArgument(hasKey(), "Either does not have a key");
+        return right();
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/GameMode.java

@@ -24,22 +24,28 @@ package com.viaversion.viaversion.api.minecraft;
 
 public enum GameMode {
 
-    NOT_SET(""),
-    SURVIVAL("Survival Mode"),
-    CREATIVE("Creative Mode"),
-    ADVENTURE("Adventure Mode"),
-    SPECTATOR("Spectator Mode");
+    NOT_SET("", -1),
+    SURVIVAL("Survival Mode", 0),
+    CREATIVE("Creative Mode", 1),
+    ADVENTURE("Adventure Mode", 2),
+    SPECTATOR("Spectator Mode", 3);
 
     private final String text;
+    private final int id;
 
-    GameMode(String text) {
+    GameMode(String text, final int id) {
         this.text = text;
+        this.id = id;
     }
 
     public String text() {
         return text;
     }
 
+    public int id() {
+        return id;
+    }
+
     public static GameMode getById(int id) {
         return switch (id) {
             case -1 -> NOT_SET;

api/src/main/java/com/viaversion/viaversion/api/minecraft/GameProfile.java

@@ -22,11 +22,35 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-public record GameProfile(@Nullable String name, @Nullable UUID id, Property[] properties) {
+public record GameProfile(@Nullable String name, @Nullable UUID id, Property[] properties, boolean dynamic) {
+
+    public GameProfile(@Nullable final String name, @Nullable final UUID id, final Property[] properties) {
+        this(name, id, properties, true);
+    }
+
+    public GameProfile(@Nullable final String name, @Nullable final UUID id) {
+        this(name, id, new Property[0]);
+    }
+
+    public Map<String, List<Property>> propertiesMap() {
+        final Map<String, List<Property>> map = new HashMap<>();
+        for (Property property : properties) {
+            map.computeIfAbsent(property.name(), k -> new ArrayList<>()).add(property);
+        }
+        return map;
+    }
 
     public record Property(String name, String value, @Nullable String signature) {
+
+        public Property(final String name, final String value) {
+            this(name, value, null);
+        }
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/Holder.java

@@ -23,6 +23,8 @@
 package com.viaversion.viaversion.api.minecraft;
 
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
 
 public interface Holder<T> {
 
@@ -88,5 +90,24 @@ public interface Holder<T> {
      * @param rewriteFunction the function to rewrite the id
      * @return a new holder with the id rewritten, or self
      */
-    Holder<T> updateId(final Int2IntFunction rewriteFunction);
+    default Holder<T> updateId(final Int2IntFunction rewriteFunction) {
+        return this.updateId(rewriteFunction, null);
+    }
+
+    /**
+     * Returns a new holder with the id rewritten using the given function, or self if this is a direct holder or the id did not change.
+     *
+     * @param rewriteFunction the function to rewrite the id
+     * @param ifMissing       a supplier that provides a new holder if the id is missing (i.e. -1)
+     * @return a new holder with the id rewritten, or self
+     */
+    Holder<T> updateId(Int2IntFunction rewriteFunction, Supplier<Holder<T>> ifMissing);
+
+    /**
+     * Returns a new holder with the value rewritten using the given function, or self if this is an id holder or the value did not change.
+     *
+     * @param rewriteFunction the function to rewrite the value
+     * @return a new holder with the value rewritten, or self
+     */
+    Holder<T> updateValue(final Function<T, T> rewriteFunction);
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/HolderSet.java

@@ -22,7 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
+import com.viaversion.nbt.tag.ListTag;
+import com.viaversion.nbt.tag.StringTag;
+import com.viaversion.nbt.tag.Tag;
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
+import java.util.function.Function;
 
 /**
  * Set of ids that either holds a string tag key or an array of ids.
@@ -32,7 +36,7 @@ public interface HolderSet {
     /**
      * Creates a new holder set for the given tag.
      *
-     * @param tagKey the tag key
+     * @param tagKey the tag key, not including '#'
      * @return a new holder set
      */
     static HolderSet of(final String tagKey) {
@@ -49,10 +53,29 @@ public interface HolderSet {
         return new HolderSetImpl.Ids(ids);
     }
 
+    static HolderSet fromTag(final Tag tag, final Function<String, Integer> mappingFunction) {
+        if (tag instanceof StringTag stringTag) {
+            if (stringTag.getValue().startsWith("#")) {
+                return HolderSet.of(stringTag.getValue().substring(1));
+            }
+
+            final int id = mappingFunction.apply(stringTag.getValue());
+            return HolderSet.of(new int[]{id});
+        } else if (tag instanceof ListTag<?> listTag) {
+            final int[] ids = new int[listTag.size()];
+            for (int i = 0; i < listTag.size(); i++) {
+                final String value = ((StringTag) listTag.get(i)).getValue();
+                ids[i] = mappingFunction.apply(value);
+            }
+            return HolderSet.of(ids);
+        }
+        throw new IllegalArgumentException();
+    }
+
     /**
-     * Gets the tag key.
+     * Gets the tag key, not including '#'.
      *
-     * @return the tag key
+     * @return the tag key without a '#'
      * @see #hasTagKey()
      */
     String tagKey();

api/src/main/java/com/viaversion/viaversion/api/minecraft/HolderSetImpl.java

@@ -67,11 +67,17 @@ final class HolderSetImpl {
 
         @Override
         public HolderSet rewrite(final Int2IntFunction idRewriter) {
+            // Filter out negative ids as they would come from missing VB mapping data. This happens especially
+            // with block ids which are not mapped and thus written as -1 so VV rewriters can cancel them nicely.
             final int[] mappedIds = new int[ids.length];
-            for (int i = 0; i < mappedIds.length; i++) {
-                mappedIds[i] = idRewriter.applyAsInt(ids[i]);
+            int validCount = 0;
+            for (final int id : ids) {
+                final int mappedId = idRewriter.applyAsInt(id);
+                if (mappedId != -1) {
+                    mappedIds[validCount++] = mappedId;
+                }
             }
-            return new Ids(mappedIds);
+            return new Ids(validCount == ids.length ? mappedIds : Arrays.copyOf(mappedIds, validCount));
         }
 
         @Override

api/src/main/java/com/viaversion/viaversion/api/minecraft/IdHolder.java

@@ -24,6 +24,8 @@ package com.viaversion.viaversion.api.minecraft;
 
 import com.google.common.base.Preconditions;
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
 
 record IdHolder<T>(int id) implements Holder<T> {
 
@@ -47,14 +49,22 @@ record IdHolder<T>(int id) implements Holder<T> {
     }
 
     @Override
-    public Holder<T> updateId(final Int2IntFunction rewriteFunction) {
+    public Holder<T> updateId(final Int2IntFunction rewriteFunction, final Supplier<Holder<T>> ifMissing) {
         final int rewrittenId = rewriteFunction.applyAsInt(id);
         if (rewrittenId == id) {
             return this;
         }
         if (rewrittenId == -1) {
+            if (ifMissing != null) {
+                return ifMissing.get();
+            }
             throw new IllegalArgumentException("Received invalid id in updateId");
         }
         return Holder.of(rewrittenId);
     }
+
+    @Override
+    public Holder<T> updateValue(final Function<T, T> rewriteFunction) {
+        return this;
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/Particle.java

@@ -22,15 +22,15 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
-import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.util.Copyable;
 import com.viaversion.viaversion.util.IdHolder;
 import io.netty.buffer.ByteBuf;
 import java.util.ArrayList;
 import java.util.List;
 
-public final class Particle implements IdHolder {
+public final class Particle implements IdHolder, Copyable {
     private final List<ParticleData<?>> arguments = new ArrayList<>(4);
     private int id;
 
@@ -73,6 +73,7 @@ public final class Particle implements IdHolder {
         arguments.set(index, new ParticleData<>(type, value));
     }
 
+    @Override
     public Particle copy() {
         final Particle particle = new Particle(id);
         for (ParticleData<?> argument : arguments) {
@@ -89,7 +90,7 @@ public final class Particle implements IdHolder {
             '}';
     }
 
-    public static final class ParticleData<T> {
+    public static final class ParticleData<T> implements Copyable {
         private final Type<T> type;
         private T value;
 
@@ -118,12 +119,9 @@ public final class Particle implements IdHolder {
             wrapper.write(type, value);
         }
 
+        @Override
         public ParticleData<T> copy() {
-            if (value instanceof Item item) {
-                return new ParticleData<>(type, (T) item.copy());
-            } else {
-                return new ParticleData<>(type, value);
-            }
+            return new ParticleData<>(type, Copyable.copy(value));
         }
 
         @Override

api/src/main/java/com/viaversion/viaversion/api/minecraft/RegistryEntry.java

@@ -23,6 +23,7 @@
 package com.viaversion.viaversion.api.minecraft;
 
 import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.util.Copyable;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
@@ -31,12 +32,13 @@ import org.checkerframework.checker.nullness.qual.Nullable;
  * @param key key of the registry entry
  * @param tag data of the registry entry, or null if the client should use its default
  */
-public record RegistryEntry(String key, @Nullable Tag tag) {
+public record RegistryEntry(String key, @Nullable Tag tag) implements Copyable {
 
     public RegistryEntry withKey(final String key) {
         return new RegistryEntry(key, tag != null ? tag.copy() : null);
     }
 
+    @Override
     public RegistryEntry copy() {
         return new RegistryEntry(key, tag != null ? tag.copy() : null);
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/ResolvableProfile.java

@@ -0,0 +1,37 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/**
+ * Profile that can be either dynamically filled by the client or is already static.
+ * The additional fields are optional overrides.
+ */
+public record ResolvableProfile(GameProfile profile, @Nullable String bodyTexture, @Nullable String capeTexture,
+                                @Nullable String elytraTexture, @Nullable Integer modelType) {
+
+    public ResolvableProfile(final GameProfile profile) {
+        this(profile, null, null, null, null);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/SoundEvent.java

@@ -22,11 +22,21 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
+import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public record SoundEvent(String identifier, @Nullable Float fixedRange) {
 
+    private static final Holder<SoundEvent> UNKNOWN = Holder.of(new SoundEvent("viaversion:unknown", 0F));
+
     public SoundEvent withIdentifier(final String identifier) {
         return new SoundEvent(identifier, this.fixedRange);
     }
+
+    public static @Nullable Holder<SoundEvent> rewriteHolder(@Nullable final Holder<SoundEvent> holder, final Int2IntFunction soundRewriteFunction) {
+        if (holder == null) {
+            return null;
+        }
+        return holder.updateId(soundRewriteFunction, () -> UNKNOWN);
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/ValueHolder.java

@@ -23,6 +23,8 @@
 package com.viaversion.viaversion.api.minecraft;
 
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
 
 record ValueHolder<T>(T value) implements Holder<T> {
 
@@ -42,7 +44,13 @@ record ValueHolder<T>(T value) implements Holder<T> {
     }
 
     @Override
-    public Holder<T> updateId(final Int2IntFunction rewriteFunction) {
+    public Holder<T> updateId(final Int2IntFunction rewriteFunction, final Supplier<Holder<T>> ifMissing) {
         return this;
     }
+
+    @Override
+    public Holder<T> updateValue(final Function<T, T> rewriteFunction) {
+        final T rewrittenValue = rewriteFunction.apply(value);
+        return rewrittenValue != value ? Holder.of(rewrittenValue) : this;
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/Vector3d.java

@@ -0,0 +1,28 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft;
+
+public record Vector3d(double x, double y, double z) {
+
+    public static final Vector3d ZERO = new Vector3d(0, 0, 0);
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/chunks/BaseChunk.java

@@ -143,6 +143,16 @@ public class BaseChunk implements Chunk {
         this.heightMap = heightMap;
     }
 
+    @Override
+    public Heightmap[] heightmaps() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void setHeightmaps(final Heightmap[] heightmaps) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public List<CompoundTag> getBlockEntities() {
         return blockEntities;

api/src/main/java/com/viaversion/viaversion/api/minecraft/chunks/Chunk.java

@@ -79,7 +79,8 @@ public interface Chunk {
      * @return chunk section bit mask, only non-null for 1.17+ chunks
      * @see #getBitmask()
      */
-    @Nullable BitSet getChunkMask();
+    @Nullable
+    BitSet getChunkMask();
 
     void setChunkMask(BitSet chunkSectionMask);
 
@@ -88,7 +89,8 @@ public interface Chunk {
      *
      * @return array of nullable chunk sections
      */
-    @Nullable ChunkSection[] getSections();
+    @Nullable
+    ChunkSection[] getSections();
 
     void setSections(ChunkSection[] sections);
 
@@ -106,10 +108,15 @@ public interface Chunk {
      *
      * @return compoundtag containing heightmaps if present
      */
-    @Nullable CompoundTag getHeightMap();
+    @Nullable
+    CompoundTag getHeightMap();
 
     void setHeightMap(@Nullable CompoundTag heightMap);
 
+    Heightmap[] heightmaps();
+
+    void setHeightmaps(Heightmap[] heightmaps);
+
     /**
      * Returns a list of block entities.
      *

api/src/main/java/com/viaversion/viaversion/api/minecraft/chunks/Chunk1_18.java

@@ -123,6 +123,16 @@ public class Chunk1_18 implements Chunk {
         this.heightMap = heightMap;
     }
 
+    @Override
+    public Heightmap[] heightmaps() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void setHeightmaps(final Heightmap[] heightmaps) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public List<CompoundTag> getBlockEntities() {
         throw new UnsupportedOperationException();

api/src/main/java/com/viaversion/viaversion/api/minecraft/chunks/Chunk1_21_5.java

@@ -0,0 +1,145 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.chunks;
+
+import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.viaversion.api.minecraft.blockentity.BlockEntity;
+import java.util.BitSet;
+import java.util.List;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class Chunk1_21_5 implements Chunk {
+    protected final int x;
+    protected final int z;
+    protected ChunkSection[] sections;
+    protected Heightmap[] heightmaps;
+    protected final List<BlockEntity> blockEntities;
+
+    public Chunk1_21_5(int x, int z, ChunkSection[] sections, Heightmap[] heightmaps, List<BlockEntity> blockEntities) {
+        this.x = x;
+        this.z = z;
+        this.sections = sections;
+        this.heightmaps = heightmaps;
+        this.blockEntities = blockEntities;
+    }
+
+    @Override
+    public boolean isBiomeData() {
+        return false;
+    }
+
+    @Override
+    public int getX() {
+        return x;
+    }
+
+    @Override
+    public int getZ() {
+        return z;
+    }
+
+    @Override
+    public boolean isFullChunk() {
+        return true;
+    }
+
+    @Override
+    public boolean isIgnoreOldLightData() {
+        return false;
+    }
+
+    @Override
+    public void setIgnoreOldLightData(boolean ignoreOldLightData) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getBitmask() {
+        return -1;
+    }
+
+    @Override
+    public void setBitmask(int bitmask) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public @Nullable BitSet getChunkMask() {
+        return null;
+    }
+
+    @Override
+    public void setChunkMask(BitSet chunkSectionMask) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChunkSection[] getSections() {
+        return sections;
+    }
+
+    @Override
+    public void setSections(ChunkSection[] sections) {
+        this.sections = sections;
+    }
+
+    @Override
+    public int @Nullable [] getBiomeData() {
+        return null;
+    }
+
+    @Override
+    public void setBiomeData(int @Nullable [] biomeData) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public @Nullable CompoundTag getHeightMap() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void setHeightMap(final CompoundTag heightMap) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Heightmap[] heightmaps() {
+        return heightmaps;
+    }
+
+    @Override
+    public void setHeightmaps(final Heightmap[] heightmaps) {
+        this.heightmaps = heightmaps;
+    }
+
+    @Override
+    public List<CompoundTag> getBlockEntities() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public List<BlockEntity> blockEntities() {
+        return blockEntities;
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/chunks/Heightmap.java

@@ -0,0 +1,26 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.chunks;
+
+public record Heightmap(int type, long[] data) {
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/CodecContext.java

@@ -0,0 +1,64 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec;
+
+import com.viaversion.viaversion.api.data.MappingData;
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.util.Key;
+import java.util.List;
+
+public interface CodecContext {
+
+    RegistryAccess registryAccess();
+
+    boolean mapped();
+
+    boolean isSupported(StructuredDataKey<?> key);
+
+    interface RegistryAccess {
+
+        Key item(int id);
+
+        Key enchantment(int id);
+
+        Key attributeModifier(int id);
+
+        Key dataComponentType(int id);
+
+        Key entity(int id);
+
+        Key blockEntity(int id);
+
+        Key sound(int id);
+
+        Key key(MappingData.MappingType mappingType, int id);
+
+        int id(MappingData.MappingType mappingType, String identifier);
+
+        static RegistryAccess of(final List<String> enchantments, final MappingData mappingData) {
+            return new RegistryAccessImpl(enchantments, mappingData);
+        }
+
+        RegistryAccess withMapped(boolean mapped);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/DelegatingOps.java

@@ -0,0 +1,110 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec;
+
+import com.viaversion.viaversion.api.type.Type;
+import java.util.function.Consumer;
+
+public class DelegatingOps implements Ops {
+
+    private final Ops delegate;
+
+    public DelegatingOps(final Ops delegate) {
+        this.delegate = delegate;
+    }
+
+    @Override
+    public CodecContext context() {
+        return delegate.context();
+    }
+
+    @Override
+    public void writeByte(final byte b) {
+        delegate.writeByte(b);
+    }
+
+    @Override
+    public void writeBytes(final byte[] array) {
+        delegate.writeBytes(array);
+    }
+
+    @Override
+    public void writeBoolean(final boolean b) {
+        delegate.writeBoolean(b);
+    }
+
+    @Override
+    public void writeShort(final short s) {
+        delegate.writeShort(s);
+    }
+
+    @Override
+    public void writeString(final CharSequence sequence) {
+        delegate.writeString(sequence);
+    }
+
+    @Override
+    public void writeInt(final int i) {
+        delegate.writeInt(i);
+    }
+
+    @Override
+    public void writeLong(final long l) {
+        delegate.writeLong(l);
+    }
+
+    @Override
+    public void writeFloat(final float f) {
+        delegate.writeFloat(f);
+    }
+
+    @Override
+    public void writeDouble(final double d) {
+        delegate.writeDouble(d);
+    }
+
+    @Override
+    public void writeInts(final int[] array) {
+        delegate.writeInts(array);
+    }
+
+    @Override
+    public void writeLongs(final long[] array) {
+        delegate.writeLongs(array);
+    }
+
+    @Override
+    public void writeList(final Consumer<ListSerializer> consumer) {
+        delegate.writeList(consumer);
+    }
+
+    @Override
+    public void writeMap(final Consumer<MapSerializer> consumer) {
+        delegate.writeMap(consumer);
+    }
+
+    @Override
+    public <V> void write(final Type<V> type, final V value) {
+        delegate.write(type, value);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/Ops.java

@@ -0,0 +1,135 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec;
+
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.Types;
+import java.util.Objects;
+import java.util.function.Consumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public interface Ops {
+
+    CodecContext context();
+
+    void writeByte(byte b);
+
+    void writeBytes(byte[] array);
+
+    void writeBoolean(boolean b);
+
+    void writeShort(short s);
+
+    void writeString(CharSequence sequence);
+
+    void writeInt(int i);
+
+    void writeLong(long l);
+
+    void writeFloat(float f);
+
+    void writeDouble(double d);
+
+    void writeInts(int[] array);
+
+    void writeLongs(long[] array);
+
+    void writeList(Consumer<ListSerializer> consumer);
+
+    void writeMap(Consumer<MapSerializer> consumer);
+
+    <V> void write(final Type<V> type, final V value);
+
+    interface ListSerializer {
+
+        <V> ListSerializer write(Type<V> valueType, V value);
+
+        ListSerializer writeList(Consumer<ListSerializer> consumer);
+
+        ListSerializer writeMap(Consumer<MapSerializer> consumer);
+    }
+
+    interface MapSerializer {
+
+        <K, V> MapSerializer write(Type<K> keyType, K key, Type<V> valueType, V value);
+
+        default <V> MapSerializer write(final String key, final Type<V> type, final V value) {
+            write(Types.STRING, key, type, value);
+            return this;
+        }
+
+        /**
+         * Writes the given value or default value if the value is null.
+         *
+         * @param key map key
+         * @param type type of the value
+         * @param value the value to write, or null
+         * @param def default value to write if the value is null
+         * @return self
+         * @param <V> value type
+         */
+        default <V> MapSerializer write(final String key, final Type<V> type, @Nullable final V value, final V def) {
+            write(Types.STRING, key, type, value != null ? value : def);
+            return this;
+        }
+
+        /**
+         * Writes the given value if it is not null.
+         *
+         * @param key map key
+         * @param type type of the value
+         * @param value the value to write, or null
+         * @return self
+         * @param <V> value type
+         */
+        default <V> MapSerializer writeOptional(final String key, final Type<V> type, @Nullable final V value) {
+            if (value != null) {
+                write(Types.STRING, key, type, value);
+            }
+            return this;
+        }
+
+        /**
+         * Writes the given value if it is not null and not equal to the default value.
+         *
+         * @param key map key
+         * @param type type of the value
+         * @param value the value to write, or null
+         * @param def default value to compare against
+         * @return self
+         * @param <V> value type
+         */
+        default <V> MapSerializer writeOptional(final String key, final Type<V> type, @Nullable final V value, final V def) {
+            if (value != null && !Objects.deepEquals(value, def)) {
+                write(Types.STRING, key, type, value);
+            }
+            return this;
+        }
+
+        MapSerializer writeList(String key, Consumer<ListSerializer> consumer);
+
+        MapSerializer writeMap(String key, Consumer<MapSerializer> consumer);
+
+        <T> MapSerializer writeInlinedMap(Type<T> valueType, T value);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/RegistryAccessImpl.java

@@ -0,0 +1,108 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec;
+
+import com.viaversion.viaversion.api.data.FullMappings;
+import com.viaversion.viaversion.api.data.MappingData;
+import com.viaversion.viaversion.util.Key;
+import java.util.List;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+final class RegistryAccessImpl implements CodecContext.RegistryAccess {
+    private final List<String> enchantments;
+    private final MappingData mappingData;
+    private final boolean mapped;
+
+    RegistryAccessImpl(final List<String> enchantments, final MappingData mappingData) {
+        this.enchantments = enchantments;
+        this.mappingData = mappingData;
+        this.mapped = false;
+    }
+
+    private RegistryAccessImpl(final List<String> enchantments, final MappingData mappingData, final boolean mapped) {
+        this.enchantments = enchantments;
+        this.mappingData = mappingData;
+        this.mapped = mapped;
+    }
+
+    @Override
+    public Key item(final int id) {
+        return key(mappingData.getFullItemMappings(), id);
+    }
+
+    @Override
+    public Key enchantment(final int id) {
+        final String identifier = id >= 0 && id < this.enchantments.size() ? this.enchantments.get(id) : null;
+        return key(identifier, id);
+    }
+
+    @Override
+    public Key attributeModifier(final int id) {
+        return key(mappingData.getAttributeMappings(), id);
+    }
+
+    @Override
+    public Key dataComponentType(final int id) {
+        return key(mappingData.getDataComponentSerializerMappings(), id);
+    }
+
+    @Override
+    public Key entity(final int id) {
+        return key(mappingData.getEntityMappings(), id);
+    }
+
+    @Override
+    public Key blockEntity(final int id) {
+        return key(mappingData.getBlockEntityMappings(), id);
+    }
+
+    @Override
+    public Key sound(final int id) {
+        return key(mappingData.getFullSoundMappings(), id);
+    }
+
+    @Override
+    public Key key(final MappingData.MappingType mappingType, final int id) {
+        return key(mappingData.getFullMappings(mappingType), id);
+    }
+
+    @Override
+    public int id(final MappingData.MappingType mappingType, final String identifier) {
+        final FullMappings mappings = mappingData.getFullMappings(mappingType);
+        return mapped ? mappings.mappedId(identifier) : mappings.id(identifier);
+    }
+
+    private Key key(final FullMappings mappings, final int id) {
+        final String identifier = mapped ? mappings.mappedIdentifier(id) : mappings.identifier(id);
+        return key(identifier, id);
+    }
+
+    private Key key(@Nullable final String identifier, final int id) {
+        return identifier != null ? Key.of(identifier) : Key.of("viaversion", "unknown/" + id);
+    }
+
+    @Override
+    public CodecContext.RegistryAccess withMapped(final boolean mapped) {
+        return this.mapped == mapped ? this : new RegistryAccessImpl(this.enchantments, this.mappingData, mapped);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/ThrowingOps.java

@@ -0,0 +1,104 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec;
+
+import com.viaversion.viaversion.api.type.Type;
+import java.util.function.Consumer;
+
+public class ThrowingOps implements Ops {
+
+    @Override
+    public CodecContext context() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeByte(final byte b) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeBytes(final byte[] array) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeBoolean(final boolean b) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeShort(final short s) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeString(final CharSequence sequence) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeInt(final int i) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeLong(final long l) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeFloat(final float f) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeDouble(final double d) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeInts(final int[] array) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeLongs(final long[] array) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeList(final Consumer<ListSerializer> consumer) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeMap(final Consumer<MapSerializer> consumer) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public <V> void write(final Type<V> type, final V value) {
+        throw new UnsupportedOperationException();
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/codec/hash/Hasher.java

@@ -0,0 +1,45 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.codec.hash;
+
+import com.viaversion.viaversion.api.minecraft.codec.Ops;
+
+/**
+ * Hash operations. Note that this is different from Vanilla codecs, where this
+ * instead acts as a (re-usable) hasher directly rather than each method having
+ * self-contained return values.
+ */
+public interface Hasher extends Ops {
+
+    /**
+     * Returns the current hash value.
+     *
+     * @return the current hash value
+     */
+    int hash();
+
+    /**
+     * Resets the hasher to its initial state.
+     */
+    void reset();
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/EmptyStructuredData.java

@@ -53,6 +53,11 @@ final class EmptyStructuredData<T> implements StructuredData<T> {
         return this.key;
     }
 
+    @Override
+    public StructuredData<T> copy() {
+        return new EmptyStructuredData<>(this.key, this.id);
+    }
+
     @Override
     public T value() {
         return null;

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/FilledStructuredData.java

@@ -23,6 +23,8 @@
 package com.viaversion.viaversion.api.minecraft.data;
 
 import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.util.ArrayUtil;
+import com.viaversion.viaversion.util.Copyable;
 import io.netty.buffer.ByteBuf;
 import java.util.Objects;
 
@@ -59,6 +61,11 @@ final class FilledStructuredData<T> implements StructuredData<T> {
         return key;
     }
 
+    @Override
+    public StructuredData<T> copy() {
+        return new FilledStructuredData<>(this.key, Copyable.copy(this.value), this.id);
+    }
+
     @Override
     public T value() {
         return value;
@@ -96,7 +103,7 @@ final class FilledStructuredData<T> implements StructuredData<T> {
     public String toString() {
         return "FilledStructuredData{" +
             "key=" + key +
-            ", value=" + value +
+            ", value=" + ArrayUtil.toString(value) +
             ", id=" + id +
             '}';
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/StructuredData.java

@@ -22,11 +22,12 @@
  */
 package com.viaversion.viaversion.api.minecraft.data;
 
+import com.viaversion.viaversion.util.Copyable;
 import com.viaversion.viaversion.util.IdHolder;
 import io.netty.buffer.ByteBuf;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-public interface StructuredData<T> extends IdHolder {
+public interface StructuredData<T> extends IdHolder, Copyable {
 
     /**
      * Returns filled structured data, equivalent to an Optional with a value in vanilla.
@@ -52,7 +53,8 @@ public interface StructuredData<T> extends IdHolder {
         return new EmptyStructuredData<>(key, id);
     }
 
-    @Nullable T value();
+    @Nullable
+    T value();
 
     void setValue(final T value);
 
@@ -60,6 +62,9 @@ public interface StructuredData<T> extends IdHolder {
 
     StructuredDataKey<T> key();
 
+    @Override
+    StructuredData<T> copy();
+
     /**
      * Returns whether the structured data is present. Even if true, the value may be null.
      *

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/StructuredDataContainer.java

@@ -26,9 +26,11 @@ import com.google.common.base.Preconditions;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.data.FullMappings;
 import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.util.Copyable;
 import com.viaversion.viaversion.util.Unit;
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 import it.unimi.dsi.fastutil.objects.Reference2ObjectOpenHashMap;
+import java.util.Collection;
 import java.util.Map;
 import java.util.function.Function;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -53,7 +55,7 @@ import org.checkerframework.checker.nullness.qual.Nullable;
  * </ul>
  * Other methods (e.g. {@link #getData(StructuredDataKey)} and {@link #has(StructuredDataKey)}) will handle both empty and non-empty data.
  */
-public final class StructuredDataContainer {
+public final class StructuredDataContainer implements Copyable {
 
     private final Map<StructuredDataKey<?>, StructuredData<?>> data;
     private FullMappings lookup;
@@ -71,7 +73,7 @@ public final class StructuredDataContainer {
     }
 
     public StructuredDataContainer() {
-        this(new Reference2ObjectOpenHashMap<>());
+        this(new Reference2ObjectOpenHashMap<>(0));
     }
 
     /**
@@ -188,6 +190,20 @@ public final class StructuredDataContainer {
         this.data.remove(key);
     }
 
+    /**
+     * Removes data by the given keys.
+     *
+     * @param keys data keys
+     * @see #replace(StructuredDataKey, Function)
+     * @see #replace(StructuredDataKey, StructuredDataKey, Function)
+     * @see #replaceKey(StructuredDataKey, StructuredDataKey)
+     */
+    public void remove(final Collection<StructuredDataKey<?>> keys) {
+        for (final StructuredDataKey<?> key : keys) {
+            this.data.remove(key);
+        }
+    }
+
     /**
      * Returns whether there is data for the given key, either empty or non-empty.
      *
@@ -225,7 +241,7 @@ public final class StructuredDataContainer {
     /**
      * Sets the lookup for serializer ids. Required to call most of the other methods.
      *
-     * @param protocol    protocol to retreive the id of the serializer from
+     * @param protocol    protocol to retrieve the id of the serializer from
      * @param mappedNames if the names are mapped (true if structures from the mapped version are added, false for the unmapped version)
      */
     public void setIdLookup(final Protocol<?, ?, ?, ?> protocol, final boolean mappedNames) {
@@ -245,8 +261,13 @@ public final class StructuredDataContainer {
         }
     }
 
+    @Override
     public StructuredDataContainer copy() {
-        final StructuredDataContainer copy = new StructuredDataContainer(new Reference2ObjectOpenHashMap<>(data));
+        final Reference2ObjectOpenHashMap<StructuredDataKey<?>, StructuredData<?>> map = new Reference2ObjectOpenHashMap<>();
+        for (final StructuredData<?> value : data.values()) {
+            map.put(value.key(), value.copy());
+        }
+        final StructuredDataContainer copy = new StructuredDataContainer(map);
         copy.lookup = this.lookup;
         return copy;
     }
@@ -263,6 +284,10 @@ public final class StructuredDataContainer {
         return data;
     }
 
+    public boolean isEmpty() {
+        return data.isEmpty();
+    }
+
     @Override
     public String toString() {
         return "StructuredDataContainer{" +

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/StructuredDataKey.java

@@ -24,70 +24,102 @@ package com.viaversion.viaversion.api.minecraft.data;
 
 import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.api.minecraft.EitherHolder;
 import com.viaversion.viaversion.api.minecraft.GameProfile;
 import com.viaversion.viaversion.api.minecraft.Holder;
-import com.viaversion.viaversion.api.minecraft.HolderSet;
-import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.minecraft.PaintingVariant;
+import com.viaversion.viaversion.api.minecraft.ResolvableProfile;
+import com.viaversion.viaversion.api.minecraft.SoundEvent;
+import com.viaversion.viaversion.api.minecraft.data.version.StructuredDataKeys1_20_5;
+import com.viaversion.viaversion.api.minecraft.data.version.StructuredDataKeys1_21_2;
+import com.viaversion.viaversion.api.minecraft.data.version.StructuredDataKeys1_21_5;
 import com.viaversion.viaversion.api.minecraft.item.data.AdventureModePredicate;
 import com.viaversion.viaversion.api.minecraft.item.data.ArmorTrim;
 import com.viaversion.viaversion.api.minecraft.item.data.AttributeModifiers1_20_5;
 import com.viaversion.viaversion.api.minecraft.item.data.AttributeModifiers1_21;
 import com.viaversion.viaversion.api.minecraft.item.data.BannerPatternLayer;
 import com.viaversion.viaversion.api.minecraft.item.data.Bee;
+import com.viaversion.viaversion.api.minecraft.item.data.BlockEntityData;
 import com.viaversion.viaversion.api.minecraft.item.data.BlockStateProperties;
+import com.viaversion.viaversion.api.minecraft.item.data.BlocksAttacks;
 import com.viaversion.viaversion.api.minecraft.item.data.Consumable1_21_2;
 import com.viaversion.viaversion.api.minecraft.item.data.CustomModelData1_21_4;
 import com.viaversion.viaversion.api.minecraft.item.data.DamageResistant;
 import com.viaversion.viaversion.api.minecraft.item.data.DeathProtection;
+import com.viaversion.viaversion.api.minecraft.item.data.DebugStickState;
 import com.viaversion.viaversion.api.minecraft.item.data.DyedColor;
+import com.viaversion.viaversion.api.minecraft.item.data.Enchantable;
 import com.viaversion.viaversion.api.minecraft.item.data.Enchantments;
+import com.viaversion.viaversion.api.minecraft.item.data.EnumTypes;
 import com.viaversion.viaversion.api.minecraft.item.data.Equippable;
-import com.viaversion.viaversion.api.minecraft.item.data.FilterableString;
 import com.viaversion.viaversion.api.minecraft.item.data.FireworkExplosion;
 import com.viaversion.viaversion.api.minecraft.item.data.Fireworks;
 import com.viaversion.viaversion.api.minecraft.item.data.FoodProperties1_20_5;
 import com.viaversion.viaversion.api.minecraft.item.data.FoodProperties1_21_2;
 import com.viaversion.viaversion.api.minecraft.item.data.Instrument1_20_5;
 import com.viaversion.viaversion.api.minecraft.item.data.Instrument1_21_2;
+import com.viaversion.viaversion.api.minecraft.item.data.ItemModel;
 import com.viaversion.viaversion.api.minecraft.item.data.JukeboxPlayable;
+import com.viaversion.viaversion.api.minecraft.item.data.LockCode;
 import com.viaversion.viaversion.api.minecraft.item.data.LodestoneTracker;
 import com.viaversion.viaversion.api.minecraft.item.data.PotDecorations;
 import com.viaversion.viaversion.api.minecraft.item.data.PotionContents;
+import com.viaversion.viaversion.api.minecraft.item.data.ProvidesTrimMaterial;
+import com.viaversion.viaversion.api.minecraft.item.data.Repairable;
 import com.viaversion.viaversion.api.minecraft.item.data.SuspiciousStewEffect;
 import com.viaversion.viaversion.api.minecraft.item.data.ToolProperties;
+import com.viaversion.viaversion.api.minecraft.item.data.TooltipDisplay;
+import com.viaversion.viaversion.api.minecraft.item.data.TropicalFishPattern;
+import com.viaversion.viaversion.api.minecraft.item.data.EntityData;
 import com.viaversion.viaversion.api.minecraft.item.data.Unbreakable;
 import com.viaversion.viaversion.api.minecraft.item.data.UseCooldown;
+import com.viaversion.viaversion.api.minecraft.item.data.Weapon;
+import com.viaversion.viaversion.api.minecraft.item.data.WritableBook;
 import com.viaversion.viaversion.api.minecraft.item.data.WrittenBook;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.ArrayType;
-import com.viaversion.viaversion.api.type.types.version.Types1_20_5;
-import com.viaversion.viaversion.api.type.types.version.Types1_21;
-import com.viaversion.viaversion.api.type.types.version.Types1_21_2;
-import com.viaversion.viaversion.api.type.types.version.Types1_21_4;
+import com.viaversion.viaversion.api.type.types.EitherType;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypes;
+import com.viaversion.viaversion.util.Either;
+import com.viaversion.viaversion.util.Key;
 import com.viaversion.viaversion.util.Unit;
 
+/**
+ * Holds data component keys.
+ *
+ * @param identifier string identifier
+ * @param type data type
+ * @param <T> data type
+ * @see VersionedTypes
+ */
 public record StructuredDataKey<T>(String identifier, Type<T> type) {
 
     public static final StructuredDataKey<CompoundTag> CUSTOM_DATA = new StructuredDataKey<>("custom_data", Types.COMPOUND_TAG);
     public static final StructuredDataKey<Integer> MAX_STACK_SIZE = new StructuredDataKey<>("max_stack_size", Types.VAR_INT);
     public static final StructuredDataKey<Integer> MAX_DAMAGE = new StructuredDataKey<>("max_damage", Types.VAR_INT);
     public static final StructuredDataKey<Integer> DAMAGE = new StructuredDataKey<>("damage", Types.VAR_INT);
-    public static final StructuredDataKey<Unbreakable> UNBREAKABLE = new StructuredDataKey<>("unbreakable", Unbreakable.TYPE);
-    public static final StructuredDataKey<Tag> CUSTOM_NAME = new StructuredDataKey<>("custom_name", Types.TAG);
-    public static final StructuredDataKey<Tag> ITEM_NAME = new StructuredDataKey<>("item_name", Types.TAG);
-    public static final StructuredDataKey<String> ITEM_MODEL = new StructuredDataKey<>("item_model", Types.STRING);
-    public static final StructuredDataKey<Tag[]> LORE = new StructuredDataKey<>("lore", new ArrayType<>(Types.TAG, 256));
-    public static final StructuredDataKey<Integer> RARITY = new StructuredDataKey<>("rarity", Types.VAR_INT);
-    public static final StructuredDataKey<Enchantments> ENCHANTMENTS = new StructuredDataKey<>("enchantments", Enchantments.TYPE);
-    public static final StructuredDataKey<AdventureModePredicate> CAN_PLACE_ON = new StructuredDataKey<>("can_place_on", AdventureModePredicate.TYPE);
-    public static final StructuredDataKey<AdventureModePredicate> CAN_BREAK = new StructuredDataKey<>("can_break", AdventureModePredicate.TYPE);
+    public static final StructuredDataKey<Unbreakable> UNBREAKABLE1_20_5 = new StructuredDataKey<>("unbreakable", Unbreakable.TYPE);
+    public static final StructuredDataKey<Unit> UNBREAKABLE1_21_5 = new StructuredDataKey<>("unbreakable", Types.EMPTY);
+    public static final StructuredDataKey<Tag> CUSTOM_NAME = new StructuredDataKey<>("custom_name", Types.TEXT_COMPONENT_TAG);
+    public static final StructuredDataKey<Tag> ITEM_NAME = new StructuredDataKey<>("item_name", Types.TEXT_COMPONENT_TAG);
+    public static final StructuredDataKey<ItemModel> ITEM_MODEL = new StructuredDataKey<>("item_model", ItemModel.TYPE);
+    public static final StructuredDataKey<Tag[]> LORE = new StructuredDataKey<>("lore", new ArrayType<>(Types.TEXT_COMPONENT_TAG, 256));
+    public static final StructuredDataKey<Integer> RARITY = new StructuredDataKey<>("rarity", EnumTypes.RARITY);
+    public static final StructuredDataKey<Enchantments> ENCHANTMENTS1_20_5 = new StructuredDataKey<>("enchantments", Enchantments.TYPE1_20_5);
+    public static final StructuredDataKey<Enchantments> ENCHANTMENTS1_21_5 = new StructuredDataKey<>("enchantments", Enchantments.TYPE1_21_5);
+    // 1.21.5+ predicates are in their own key classes
+    public static final StructuredDataKey<AdventureModePredicate> CAN_PLACE_ON1_20_5 = new StructuredDataKey<>("can_place_on", AdventureModePredicate.TYPE1_20_5);
+    public static final StructuredDataKey<AdventureModePredicate> CAN_BREAK1_20_5 = new StructuredDataKey<>("can_break", AdventureModePredicate.TYPE1_20_5);
     public static final StructuredDataKey<AttributeModifiers1_20_5> ATTRIBUTE_MODIFIERS1_20_5 = new StructuredDataKey<>("attribute_modifiers", AttributeModifiers1_20_5.TYPE);
-    public static final StructuredDataKey<AttributeModifiers1_21> ATTRIBUTE_MODIFIERS1_21 = new StructuredDataKey<>("attribute_modifiers", AttributeModifiers1_21.TYPE);
+    public static final StructuredDataKey<AttributeModifiers1_21> ATTRIBUTE_MODIFIERS1_21 = new StructuredDataKey<>("attribute_modifiers", AttributeModifiers1_21.TYPE1_21);
+    public static final StructuredDataKey<AttributeModifiers1_21> ATTRIBUTE_MODIFIERS1_21_5 = new StructuredDataKey<>("attribute_modifiers", AttributeModifiers1_21.TYPE1_21_5);
+    public static final StructuredDataKey<AttributeModifiers1_21> ATTRIBUTE_MODIFIERS1_21_6 = new StructuredDataKey<>("attribute_modifiers", AttributeModifiers1_21.TYPE1_21_6);
     public static final StructuredDataKey<Integer> CUSTOM_MODEL_DATA1_20_5 = new StructuredDataKey<>("custom_model_data", Types.VAR_INT);
     public static final StructuredDataKey<CustomModelData1_21_4> CUSTOM_MODEL_DATA1_21_4 = new StructuredDataKey<>("custom_model_data", CustomModelData1_21_4.TYPE);
     public static final StructuredDataKey<Unit> HIDE_ADDITIONAL_TOOLTIP = new StructuredDataKey<>("hide_additional_tooltip", Types.EMPTY);
     public static final StructuredDataKey<Unit> HIDE_TOOLTIP = new StructuredDataKey<>("hide_tooltip", Types.EMPTY);
+    public static final StructuredDataKey<TooltipDisplay> TOOLTIP_DISPLAY = new StructuredDataKey<>("tooltip_display", TooltipDisplay.TYPE);
     public static final StructuredDataKey<Integer> REPAIR_COST = new StructuredDataKey<>("repair_cost", Types.VAR_INT);
     public static final StructuredDataKey<Unit> CREATIVE_SLOT_LOCK = new StructuredDataKey<>("creative_slot_lock", Types.EMPTY);
     public static final StructuredDataKey<Boolean> ENCHANTMENT_GLINT_OVERRIDE = new StructuredDataKey<>("enchantment_glint_override", Types.BOOLEAN);
@@ -96,65 +128,104 @@ public record StructuredDataKey<T>(String identifier, Type<T> type) {
     public static final StructuredDataKey<FoodProperties1_20_5> FOOD1_21 = new StructuredDataKey<>("food", FoodProperties1_20_5.TYPE1_21);
     public static final StructuredDataKey<FoodProperties1_21_2> FOOD1_21_2 = new StructuredDataKey<>("food", FoodProperties1_21_2.TYPE);
     public static final StructuredDataKey<Consumable1_21_2> CONSUMABLE1_21_2 = new StructuredDataKey<>("consumable", Consumable1_21_2.TYPE);
-    public static final StructuredDataKey<Item> USE_REMAINDER1_21_2 = new StructuredDataKey<>("use_remainder", Types1_21_2.ITEM);
-    public static final StructuredDataKey<Item> USE_REMAINDER1_21_4 = new StructuredDataKey<>("use_remainder", Types1_21_4.ITEM);
     public static final StructuredDataKey<UseCooldown> USE_COOLDOWN = new StructuredDataKey<>("use_cooldown", UseCooldown.TYPE);
     public static final StructuredDataKey<Unit> FIRE_RESISTANT = new StructuredDataKey<>("fire_resistant", Types.EMPTY);
     public static final StructuredDataKey<DamageResistant> DAMAGE_RESISTANT = new StructuredDataKey<>("damage_resistant", DamageResistant.TYPE);
-    public static final StructuredDataKey<ToolProperties> TOOL = new StructuredDataKey<>("tool", ToolProperties.TYPE);
-    public static final StructuredDataKey<Integer> ENCHANTABLE = new StructuredDataKey<>("enchantable", Types.VAR_INT);
-    public static final StructuredDataKey<Equippable> EQUIPPABLE = new StructuredDataKey<>("equippable", Equippable.TYPE);
-    public static final StructuredDataKey<HolderSet> REPAIRABLE = new StructuredDataKey<>("repairable", Types.HOLDER_SET);
+    public static final StructuredDataKey<ToolProperties> TOOL1_20_5 = new StructuredDataKey<>("tool", ToolProperties.TYPE1_20_5);
+    public static final StructuredDataKey<ToolProperties> TOOL1_21_5 = new StructuredDataKey<>("tool", ToolProperties.TYPE1_21_5);
+    public static final StructuredDataKey<Weapon> WEAPON = new StructuredDataKey<>("weapon", Weapon.TYPE);
+    public static final StructuredDataKey<Enchantable> ENCHANTABLE = new StructuredDataKey<>("enchantable", Enchantable.TYPE);
+    public static final StructuredDataKey<Equippable> EQUIPPABLE1_21_2 = new StructuredDataKey<>("equippable", Equippable.TYPE1_21_2);
+    public static final StructuredDataKey<Equippable> EQUIPPABLE1_21_5 = new StructuredDataKey<>("equippable", Equippable.TYPE1_21_5);
+    public static final StructuredDataKey<Equippable> EQUIPPABLE1_21_6 = new StructuredDataKey<>("equippable", Equippable.TYPE1_21_6);
+    public static final StructuredDataKey<Repairable> REPAIRABLE = new StructuredDataKey<>("repairable", Repairable.TYPE);
     public static final StructuredDataKey<Unit> GLIDER = new StructuredDataKey<>("glider", Types.EMPTY);
-    public static final StructuredDataKey<String> TOOLTIP_STYLE = new StructuredDataKey<>("tooltip_style", Types.STRING);
+    public static final StructuredDataKey<Key> TOOLTIP_STYLE = new StructuredDataKey<>("tooltip_style", Types.RESOURCE_LOCATION);
     public static final StructuredDataKey<DeathProtection> DEATH_PROTECTION = new StructuredDataKey<>("death_protection", DeathProtection.TYPE);
-    public static final StructuredDataKey<Enchantments> STORED_ENCHANTMENTS = new StructuredDataKey<>("stored_enchantments", Enchantments.TYPE);
-    public static final StructuredDataKey<DyedColor> DYED_COLOR = new StructuredDataKey<>("dyed_color", DyedColor.TYPE);
+    public static final StructuredDataKey<BlocksAttacks> BLOCKS_ATTACKS = new StructuredDataKey<>("blocks_attacks", BlocksAttacks.TYPE);
+    public static final StructuredDataKey<Enchantments> STORED_ENCHANTMENTS1_20_5 = new StructuredDataKey<>("stored_enchantments", Enchantments.TYPE1_20_5);
+    public static final StructuredDataKey<Enchantments> STORED_ENCHANTMENTS1_21_5 = new StructuredDataKey<>("stored_enchantments", Enchantments.TYPE1_21_5);
+    public static final StructuredDataKey<DyedColor> DYED_COLOR1_20_5 = new StructuredDataKey<>("dyed_color", DyedColor.TYPE1_20_5);
+    public static final StructuredDataKey<DyedColor> DYED_COLOR1_21_5 = new StructuredDataKey<>("dyed_color", DyedColor.TYPE1_21_5);
     public static final StructuredDataKey<Integer> MAP_COLOR = new StructuredDataKey<>("map_color", Types.INT);
     public static final StructuredDataKey<Integer> MAP_ID = new StructuredDataKey<>("map_id", Types.VAR_INT);
     public static final StructuredDataKey<CompoundTag> MAP_DECORATIONS = new StructuredDataKey<>("map_decorations", Types.COMPOUND_TAG);
     public static final StructuredDataKey<Integer> MAP_POST_PROCESSING = new StructuredDataKey<>("map_post_processing", Types.VAR_INT);
-    public static final StructuredDataKey<Item[]> CHARGED_PROJECTILES1_20_5 = new StructuredDataKey<>("charged_projectiles", Types1_20_5.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> CHARGED_PROJECTILES1_21 = new StructuredDataKey<>("charged_projectiles", Types1_21.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> CHARGED_PROJECTILES1_21_2 = new StructuredDataKey<>("charged_projectiles", Types1_21_2.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> CHARGED_PROJECTILES1_21_4 = new StructuredDataKey<>("charged_projectiles", Types1_21_4.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> BUNDLE_CONTENTS1_20_5 = new StructuredDataKey<>("bundle_contents", Types1_20_5.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> BUNDLE_CONTENTS1_21 = new StructuredDataKey<>("bundle_contents", Types1_21.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> BUNDLE_CONTENTS1_21_2 = new StructuredDataKey<>("bundle_contents", Types1_21_2.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> BUNDLE_CONTENTS1_21_4 = new StructuredDataKey<>("bundle_contents", Types1_21_4.ITEM_ARRAY);
     public static final StructuredDataKey<PotionContents> POTION_CONTENTS1_20_5 = new StructuredDataKey<>("potion_contents", PotionContents.TYPE1_20_5);
     public static final StructuredDataKey<PotionContents> POTION_CONTENTS1_21_2 = new StructuredDataKey<>("potion_contents", PotionContents.TYPE1_21_2);
+    public static final StructuredDataKey<Float> POTION_DURATION_SCALE = new StructuredDataKey<>("potion_duration_scale", Types.FLOAT);
     public static final StructuredDataKey<SuspiciousStewEffect[]> SUSPICIOUS_STEW_EFFECTS = new StructuredDataKey<>("suspicious_stew_effects", SuspiciousStewEffect.ARRAY_TYPE);
-    public static final StructuredDataKey<FilterableString[]> WRITABLE_BOOK_CONTENT = new StructuredDataKey<>("writable_book_content", FilterableString.ARRAY_TYPE);
+    public static final StructuredDataKey<WritableBook> WRITABLE_BOOK_CONTENT = new StructuredDataKey<>("writable_book_content", WritableBook.TYPE);
     public static final StructuredDataKey<WrittenBook> WRITTEN_BOOK_CONTENT = new StructuredDataKey<>("written_book_content", WrittenBook.TYPE);
     public static final StructuredDataKey<ArmorTrim> TRIM1_20_5 = new StructuredDataKey<>("trim", ArmorTrim.TYPE1_20_5);
     public static final StructuredDataKey<ArmorTrim> TRIM1_21_2 = new StructuredDataKey<>("trim", ArmorTrim.TYPE1_21_2);
     public static final StructuredDataKey<ArmorTrim> TRIM1_21_4 = new StructuredDataKey<>("trim", ArmorTrim.TYPE1_21_4);
-    public static final StructuredDataKey<CompoundTag> DEBUG_STICK_STATE = new StructuredDataKey<>("debug_stick_state", Types.COMPOUND_TAG);
-    public static final StructuredDataKey<CompoundTag> ENTITY_DATA = new StructuredDataKey<>("entity_data", Types.COMPOUND_TAG);
+    public static final StructuredDataKey<ArmorTrim> TRIM1_21_5 = new StructuredDataKey<>("trim", ArmorTrim.TYPE1_21_5);
+    public static final StructuredDataKey<DebugStickState> DEBUG_STICK_STATE = new StructuredDataKey<>("debug_stick_state", DebugStickState.TYPE);
+    public static final StructuredDataKey<CompoundTag> ENTITY_DATA1_20_5 = new StructuredDataKey<>("entity_data", Types.COMPOUND_TAG);
+    public static final StructuredDataKey<EntityData> ENTITY_DATA1_21_9 = new StructuredDataKey<>("entity_data", EntityData.TYPE);
     public static final StructuredDataKey<CompoundTag> BUCKET_ENTITY_DATA = new StructuredDataKey<>("bucket_entity_data", Types.COMPOUND_TAG);
-    public static final StructuredDataKey<CompoundTag> BLOCK_ENTITY_DATA = new StructuredDataKey<>("block_entity_data", Types.COMPOUND_TAG);
+    public static final StructuredDataKey<CompoundTag> BLOCK_ENTITY_DATA1_20_5 = new StructuredDataKey<>("block_entity_data", Types.COMPOUND_TAG);
+    public static final StructuredDataKey<BlockEntityData> BLOCK_ENTITY_DATA1_21_9 = new StructuredDataKey<>("block_entity_data", BlockEntityData.TYPE);
     public static final StructuredDataKey<Holder<Instrument1_20_5>> INSTRUMENT1_20_5 = new StructuredDataKey<>("instrument", Instrument1_20_5.TYPE);
     public static final StructuredDataKey<Holder<Instrument1_21_2>> INSTRUMENT1_21_2 = new StructuredDataKey<>("instrument", Instrument1_21_2.TYPE);
+    public static final StructuredDataKey<EitherHolder<Instrument1_21_2>> INSTRUMENT1_21_5 = new StructuredDataKey<>("instrument", Instrument1_21_2.EITHER_HOLDER_TYPE);
+    public static final StructuredDataKey<ProvidesTrimMaterial> PROVIDES_TRIM_MATERIAL = new StructuredDataKey<>("provides_trim_material", ProvidesTrimMaterial.TYPE);
     public static final StructuredDataKey<Integer> OMINOUS_BOTTLE_AMPLIFIER = new StructuredDataKey<>("ominous_bottle_amplifier", Types.VAR_INT);
-    public static final StructuredDataKey<JukeboxPlayable> JUKEBOX_PLAYABLE = new StructuredDataKey<>("jukebox_playable", JukeboxPlayable.TYPE);
+    public static final StructuredDataKey<JukeboxPlayable> JUKEBOX_PLAYABLE1_21 = new StructuredDataKey<>("jukebox_playable", JukeboxPlayable.TYPE1_21);
+    public static final StructuredDataKey<JukeboxPlayable> JUKEBOX_PLAYABLE1_21_5 = new StructuredDataKey<>("jukebox_playable", JukeboxPlayable.TYPE1_21_5);
+    public static final StructuredDataKey<Key> PROVIDES_BANNER_PATTERNS = new StructuredDataKey<>("provides_banner_patterns", Types.TAG_KEY);
     public static final StructuredDataKey<Tag> RECIPES = new StructuredDataKey<>("recipes", Types.TAG);
     public static final StructuredDataKey<LodestoneTracker> LODESTONE_TRACKER = new StructuredDataKey<>("lodestone_tracker", LodestoneTracker.TYPE);
     public static final StructuredDataKey<FireworkExplosion> FIREWORK_EXPLOSION = new StructuredDataKey<>("firework_explosion", FireworkExplosion.TYPE);
     public static final StructuredDataKey<Fireworks> FIREWORKS = new StructuredDataKey<>("fireworks", Fireworks.TYPE);
-    public static final StructuredDataKey<GameProfile> PROFILE = new StructuredDataKey<>("profile", Types.GAME_PROFILE);
-    public static final StructuredDataKey<String> NOTE_BLOCK_SOUND = new StructuredDataKey<>("note_block_sound", Types.STRING);
+    public static final StructuredDataKey<GameProfile> PROFILE1_20_5 = new StructuredDataKey<>("profile", Types.GAME_PROFILE);
+    public static final StructuredDataKey<ResolvableProfile> PROFILE1_21_9 = new StructuredDataKey<>("profile", Types.RESOLVABLE_PROFILE);
+    public static final StructuredDataKey<Key> NOTE_BLOCK_SOUND = new StructuredDataKey<>("note_block_sound", Types.RESOURCE_LOCATION);
     public static final StructuredDataKey<BannerPatternLayer[]> BANNER_PATTERNS = new StructuredDataKey<>("banner_patterns", BannerPatternLayer.ARRAY_TYPE);
-    public static final StructuredDataKey<Integer> BASE_COLOR = new StructuredDataKey<>("base_color", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> BASE_COLOR = new StructuredDataKey<>("base_color", EnumTypes.DYE_COLOR);
     public static final StructuredDataKey<PotDecorations> POT_DECORATIONS = new StructuredDataKey<>("pot_decorations", PotDecorations.TYPE);
-    public static final StructuredDataKey<Item[]> CONTAINER1_20_5 = new StructuredDataKey<>("container", Types1_20_5.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> CONTAINER1_21 = new StructuredDataKey<>("container", Types1_21.ITEM_ARRAY);
-    public static final StructuredDataKey<Item[]> CONTAINER1_21_2 = new StructuredDataKey<>("container", new ArrayType<>(Types1_21_2.ITEM, 256));
-    public static final StructuredDataKey<Item[]> CONTAINER1_21_4 = new StructuredDataKey<>("container", Types1_21_4.ITEM_ARRAY);
     public static final StructuredDataKey<BlockStateProperties> BLOCK_STATE = new StructuredDataKey<>("block_state", BlockStateProperties.TYPE);
-    public static final StructuredDataKey<Bee[]> BEES = new StructuredDataKey<>("bees", Bee.ARRAY_TYPE);
-    public static final StructuredDataKey<Tag> LOCK = new StructuredDataKey<>("lock", Types.TAG);
+    public static final StructuredDataKey<Bee[]> BEES1_20_5 = new StructuredDataKey<>("bees", Bee.ARRAY_TYPE1_20_5);
+    public static final StructuredDataKey<Bee[]> BEES1_21_9 = new StructuredDataKey<>("bees", Bee.ARRAY_TYPE1_21_9);
+    public static final StructuredDataKey<Tag> LOCK1_20_5 = new StructuredDataKey<>("lock", Types.TAG);
+    public static final StructuredDataKey<LockCode> LOCK1_21_2 = new StructuredDataKey<>("lock", LockCode.TYPE);
     public static final StructuredDataKey<CompoundTag> CONTAINER_LOOT = new StructuredDataKey<>("container_loot", Types.COMPOUND_TAG);
+    public static final StructuredDataKey<Holder<SoundEvent>> BREAK_SOUND = new StructuredDataKey<>("break_sound", Types.SOUND_EVENT);
+
+    public static final StructuredDataKey<Integer> VILLAGER_VARIANT = new StructuredDataKey<>("villager/variant", EnumTypes.VILLAGER_TYPE);
+    public static final StructuredDataKey<Integer> WOLF_VARIANT = new StructuredDataKey<>("wolf/variant", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> WOLF_SOUND_VARIANT = new StructuredDataKey<>("wolf/sound_variant", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> WOLF_COLLAR = new StructuredDataKey<>("wolf/collar", EnumTypes.DYE_COLOR);
+    public static final StructuredDataKey<Integer> FOX_VARIANT = new StructuredDataKey<>("fox/variant", EnumTypes.FOX_VARIANT);
+    public static final StructuredDataKey<Integer> SALMON_SIZE = new StructuredDataKey<>("salmon/size", EnumTypes.SALMON_VARIANT);
+    public static final StructuredDataKey<Integer> PARROT_VARIANT = new StructuredDataKey<>("parrot/variant", EnumTypes.PARROT_VARIANT);
+    public static final StructuredDataKey<TropicalFishPattern> TROPICAL_FISH_PATTERN = new StructuredDataKey<>("tropical_fish/pattern", TropicalFishPattern.TYPE);
+    public static final StructuredDataKey<Integer> TROPICAL_FISH_BASE_COLOR = new StructuredDataKey<>("tropical_fish/base_color", EnumTypes.DYE_COLOR);
+    public static final StructuredDataKey<Integer> TROPICAL_FISH_PATTERN_COLOR = new StructuredDataKey<>("tropical_fish/pattern_color", EnumTypes.DYE_COLOR);
+    public static final StructuredDataKey<Integer> MOOSHROOM_VARIANT = new StructuredDataKey<>("mooshroom/variant", EnumTypes.MUSHROOM_COW_VARIANT);
+    public static final StructuredDataKey<Integer> RABBIT_VARIANT = new StructuredDataKey<>("rabbit/variant", EnumTypes.RABBIT_VARIANT);
+    public static final StructuredDataKey<Integer> PIG_VARIANT = new StructuredDataKey<>("pig/variant", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> COW_VARIANT = new StructuredDataKey<>("cow/variant", Types.VAR_INT);
+    public static final StructuredDataKey<Either<Integer, String>> CHICKEN_VARIANT = new StructuredDataKey<>("chicken/variant", new EitherType<>(Types.VAR_INT, Types.STRING)); // ???
+    public static final StructuredDataKey<Integer> FROG_VARIANT = new StructuredDataKey<>("frog/variant", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> HORSE_VARIANT = new StructuredDataKey<>("horse/variant", EnumTypes.HORSE_VARIANT);
+    public static final StructuredDataKey<Holder<PaintingVariant>> PAINTING_VARIANT = new StructuredDataKey<>("painting/variant", PaintingVariant.TYPE1_21_2);
+    public static final StructuredDataKey<Integer> LLAMA_VARIANT = new StructuredDataKey<>("llama/variant", EnumTypes.LLAMA_VARIANT);
+    public static final StructuredDataKey<Integer> AXOLOTL_VARIANT = new StructuredDataKey<>("axolotl/variant", EnumTypes.AXOLOTL_VARIANT);
+    public static final StructuredDataKey<Integer> CAT_VARIANT = new StructuredDataKey<>("cat/variant", Types.VAR_INT);
+    public static final StructuredDataKey<Integer> CAT_COLLAR = new StructuredDataKey<>("cat/collar", EnumTypes.DYE_COLOR);
+    public static final StructuredDataKey<Integer> SHEEP_COLOR = new StructuredDataKey<>("sheep/color", EnumTypes.DYE_COLOR);
+    public static final StructuredDataKey<Integer> SHULKER_COLOR = new StructuredDataKey<>("shulker/color", EnumTypes.DYE_COLOR);
+
+    // These are only safe to use after protocol loading
+    public static final StructuredDataKeys1_20_5 V1_20_5 = VersionedTypes.V1_20_5.structuredDataKeys();
+    public static final StructuredDataKeys1_20_5 V1_21 = VersionedTypes.V1_21.structuredDataKeys();
+    public static final StructuredDataKeys1_21_2 V1_21_2 = VersionedTypes.V1_21_2.structuredDataKeys();
+    public static final StructuredDataKeys1_21_2 V1_21_4 = VersionedTypes.V1_21_4.structuredDataKeys();
+    public static final StructuredDataKeys1_21_5 V1_21_5 = VersionedTypes.V1_21_5.structuredDataKeys();
+    public static final StructuredDataKeys1_21_5 V1_21_6 = VersionedTypes.V1_21_6.structuredDataKeys();
+    public static final StructuredDataKeys1_21_5 V1_21_9 = VersionedTypes.V1_21_9.structuredDataKeys();
 
     @Override
     public String toString() {

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/predicate/DataComponentMatchers.java

@@ -0,0 +1,52 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.predicate;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredData;
+import com.viaversion.viaversion.api.type.Type;
+import io.netty.buffer.ByteBuf;
+
+public record DataComponentMatchers(StructuredData<?>[] exactPredicates, DataComponentPredicate[] predicates) {
+
+    public static final class DataComponentMatchersType extends Type<DataComponentMatchers> {
+        private final Type<StructuredData<?>[]> dataArrayType;
+
+        public DataComponentMatchersType(final Type<StructuredData<?>[]> dataArrayType) {
+            super(DataComponentMatchers.class);
+            this.dataArrayType = dataArrayType;
+        }
+
+        @Override
+        public DataComponentMatchers read(final ByteBuf buffer) {
+            final StructuredData<?>[] exactPredicates = dataArrayType.read(buffer);
+            final DataComponentPredicate[] partialPredicates = DataComponentPredicate.ARRAY_TYPE.read(buffer);
+            return new DataComponentMatchers(exactPredicates, partialPredicates);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final DataComponentMatchers value) {
+            dataArrayType.write(buffer, value.exactPredicates());
+            DataComponentPredicate.ARRAY_TYPE.write(buffer, value.predicates());
+        }
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/predicate/DataComponentPredicate.java

@@ -0,0 +1,48 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.predicate;
+
+import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.api.type.types.ArrayType;
+import io.netty.buffer.ByteBuf;
+
+public record DataComponentPredicate(int id, Tag predicate) {
+
+    public static final Type<DataComponentPredicate> TYPE = new Type<>(DataComponentPredicate.class) {
+        @Override
+        public DataComponentPredicate read(final ByteBuf buffer) {
+            final int id = Types.VAR_INT.readPrimitive(buffer);
+            final Tag predicate = Types.TAG.read(buffer);
+            return new DataComponentPredicate(id, predicate);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final DataComponentPredicate value) {
+            Types.VAR_INT.writePrimitive(buffer, value.id());
+            Types.TAG.write(buffer, value.predicate());
+        }
+    };
+    public static final Type<DataComponentPredicate[]> ARRAY_TYPE = new ArrayType<>(TYPE, 64);
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/version/StructuredDataKeys1_20_5.java

@@ -0,0 +1,40 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.version;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
+
+public class StructuredDataKeys1_20_5 extends VersionedStructuredDataKeys {
+
+    public final StructuredDataKey<Item[]> container;
+    public final StructuredDataKey<Item[]> chargedProjectiles;
+    public final StructuredDataKey<Item[]> bundleContents;
+
+    public StructuredDataKeys1_20_5(final VersionedTypesHolder types) {
+        this.container = add("container", types.itemArray());
+        this.chargedProjectiles = add("charged_projectiles", types.itemArray());
+        this.bundleContents = add("bundle_contents", types.itemArray());
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/version/StructuredDataKeys1_21_2.java

@@ -0,0 +1,43 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.version;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.minecraft.item.data.ContainterContents.ContainerContentsType;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
+
+public class StructuredDataKeys1_21_2 extends VersionedStructuredDataKeys {
+
+    public final StructuredDataKey<Item[]> container;
+    public final StructuredDataKey<Item[]> chargedProjectiles;
+    public final StructuredDataKey<Item[]> bundleContents;
+    public final StructuredDataKey<Item> useRemainder;
+
+    public StructuredDataKeys1_21_2(final VersionedTypesHolder types) {
+        this.container = add("container", new ContainerContentsType(types.item()));
+        this.chargedProjectiles = add("charged_projectiles", types.itemArray());
+        this.bundleContents = add("bundle_contents", types.itemArray());
+        this.useRemainder = add("use_remainder", types.item());
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/version/StructuredDataKeys1_21_5.java

@@ -0,0 +1,43 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.version;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.api.minecraft.item.data.AdventureModePredicate;
+import com.viaversion.viaversion.api.minecraft.item.data.AdventureModePredicate.AdventureModePredicateType1_21_5;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
+
+public class StructuredDataKeys1_21_5 extends StructuredDataKeys1_21_2 {
+
+    public final StructuredDataKey<AdventureModePredicate> canPlaceOn;
+    public final StructuredDataKey<AdventureModePredicate> canBreak;
+
+    public StructuredDataKeys1_21_5(final VersionedTypesHolder types) {
+        super(types);
+        final AdventureModePredicateType1_21_5 adventureModePredicateType = new AdventureModePredicateType1_21_5(types.structuredDataArray());
+        this.canPlaceOn = add("can_place_on", adventureModePredicateType);
+        this.canBreak = add("can_break", adventureModePredicateType);
+        this.unsupportedForOps.add(this.canPlaceOn);
+        this.unsupportedForOps.add(this.canBreak);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/version/VersionedStructuredDataKeys.java

@@ -0,0 +1,50 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.data.version;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.api.type.Type;
+import it.unimi.dsi.fastutil.objects.ReferenceArraySet;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+public abstract class VersionedStructuredDataKeys {
+
+    private final List<StructuredDataKey<?>> keys = new ArrayList<>();
+    protected final Set<StructuredDataKey<?>> unsupportedForOps = new ReferenceArraySet<>();
+
+    protected <T> StructuredDataKey<T> add(final String identifier, final Type<T> type) {
+        final StructuredDataKey<T> key = new StructuredDataKey<>(identifier, type);
+        this.keys.add(key);
+        return key;
+    }
+
+    public List<StructuredDataKey<?>> keys() {
+        return this.keys;
+    }
+
+    public boolean supportsOps(final StructuredDataKey<?> key) {
+        return !unsupportedForOps.contains(key);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_10.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_10 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -154,7 +143,7 @@ public class EntityTypes1_10 {
         SPIDER(52, ABSTRACT_MONSTER),
         CAVE_SPIDER(59, SPIDER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -195,7 +184,9 @@ public class EntityTypes1_10 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -212,7 +203,13 @@ public class EntityTypes1_10 {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
         AREA_EFFECT_CLOUD(3, EntityType.AREA_EFFECT_CLOUD),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -235,19 +232,25 @@ public class EntityTypes1_10 {
         SPECTRAL_ARROW(91, EntityType.SPECTRAL_ARROW),
         DRAGON_FIREBALL(93, EntityType.DRAGON_FIREBALL);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -256,20 +259,28 @@ public class EntityTypes1_10 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_11.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_11 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -179,7 +168,7 @@ public class EntityTypes1_11 {
         EVOKER(34, ABSTRACT_MONSTER),
         VINDICATOR(36, ABSTRACT_MONSTER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -220,7 +209,9 @@ public class EntityTypes1_11 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -237,7 +228,13 @@ public class EntityTypes1_11 {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
         AREA_EFFECT_CLOUD(3, EntityType.AREA_EFFECT_CLOUD),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -262,19 +259,25 @@ public class EntityTypes1_11 {
         SPECTRAL_ARROW(91, EntityType.SPECTRAL_ARROW),
         DRAGON_FIREBALL(93, EntityType.DRAGON_FIREBALL);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -283,20 +286,28 @@ public class EntityTypes1_11 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_12.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_12 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -185,7 +174,7 @@ public class EntityTypes1_12 {
         EVOKER(34, SPELLCASTER_ILLAGER),
         ILLUSIONER(37, SPELLCASTER_ILLAGER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -226,7 +215,9 @@ public class EntityTypes1_12 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -243,7 +234,13 @@ public class EntityTypes1_12 {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
         AREA_EFFECT_CLOUD(3, EntityType.AREA_EFFECT_CLOUD),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -268,19 +265,25 @@ public class EntityTypes1_12 {
         SPECTRAL_ARROW(91, EntityType.SPECTRAL_ARROW),
         DRAGON_FIREBALL(93, EntityType.DRAGON_FIREBALL);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -289,20 +292,28 @@ public class EntityTypes1_12 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_13.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_13 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -196,7 +185,7 @@ public class EntityTypes1_13 {
         EVOKER(21, SPELLCASTER_ILLAGER),
         ILLUSIONER(31, SPELLCASTER_ILLAGER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -237,7 +226,9 @@ public class EntityTypes1_13 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -254,7 +245,13 @@ public class EntityTypes1_13 {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
         AREA_EFFECT_CLOUD(3, EntityType.AREA_EFFECT_CLOUD),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -280,19 +277,25 @@ public class EntityTypes1_13 {
         DRAGON_FIREBALL(93, EntityType.DRAGON_FIREBALL),
         TRIDENT(94, EntityType.TRIDENT);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -301,20 +304,28 @@ public class EntityTypes1_13 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_14.java

@@ -213,7 +213,7 @@ public enum EntityTypes1_14 implements EntityType {
 
     EntityTypes1_14(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_14(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_15.java

@@ -214,7 +214,7 @@ public enum EntityTypes1_15 implements EntityType {
 
     EntityTypes1_15(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_15(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_16.java

@@ -218,7 +218,7 @@ public enum EntityTypes1_16 implements EntityType {
 
     EntityTypes1_16(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_16(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_16_2.java

@@ -221,7 +221,7 @@ public enum EntityTypes1_16_2 implements EntityType {
 
     EntityTypes1_16_2(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_16_2(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_17.java

@@ -227,7 +227,7 @@ public enum EntityTypes1_17 implements EntityType {
 
     EntityTypes1_17(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_17(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_19.java

@@ -232,7 +232,7 @@ public enum EntityTypes1_19 implements EntityType {
 
     EntityTypes1_19(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_19(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_19_3.java

@@ -233,7 +233,7 @@ public enum EntityTypes1_19_3 implements EntityType {
 
     EntityTypes1_19_3(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_19_3(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_19_4.java

@@ -240,7 +240,7 @@ public enum EntityTypes1_19_4 implements EntityType {
 
     EntityTypes1_19_4(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_19_4(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_20_3.java

@@ -242,7 +242,7 @@ public enum EntityTypes1_20_3 implements EntityType {
 
     EntityTypes1_20_3(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_20_3(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_20_5.java

@@ -248,7 +248,7 @@ public enum EntityTypes1_20_5 implements EntityType {
 
     EntityTypes1_20_5(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_20_5(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_21_2.java

@@ -272,7 +272,7 @@ public enum EntityTypes1_21_2 implements EntityType {
 
     EntityTypes1_21_2(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_21_2(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_21_4.java

@@ -271,7 +271,7 @@ public enum EntityTypes1_21_4 implements EntityType {
 
     EntityTypes1_21_4(final EntityType parent) {
         this.parent = parent;
-        this.identifier =  Key.namespaced(name().toLowerCase(Locale.ROOT));
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
     }
 
     EntityTypes1_21_4(final EntityType parent, @Nullable final String identifier) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_21_5.java

@@ -0,0 +1,317 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.entities;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.util.EntityTypeUtil;
+import com.viaversion.viaversion.util.Key;
+import java.util.Locale;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public enum EntityTypes1_21_5 implements EntityType {
+
+    ENTITY(null, null),
+
+    AREA_EFFECT_CLOUD(ENTITY),
+    END_CRYSTAL(ENTITY),
+    EVOKER_FANGS(ENTITY),
+    EXPERIENCE_ORB(ENTITY),
+    EYE_OF_ENDER(ENTITY),
+    FALLING_BLOCK(ENTITY),
+    ITEM(ENTITY),
+    TNT(ENTITY),
+    OMINOUS_ITEM_SPAWNER(ENTITY),
+    MARKER(ENTITY),
+    LIGHTNING_BOLT(ENTITY),
+    INTERACTION(ENTITY),
+
+    DISPLAY(ENTITY, null),
+    BLOCK_DISPLAY(DISPLAY),
+    ITEM_DISPLAY(DISPLAY),
+    TEXT_DISPLAY(DISPLAY),
+
+    // Hanging entities
+    HANGING_ENTITY(ENTITY, null),
+    LEASH_KNOT(HANGING_ENTITY),
+    PAINTING(HANGING_ENTITY),
+    ITEM_FRAME(HANGING_ENTITY),
+    GLOW_ITEM_FRAME(ITEM_FRAME),
+
+    // Projectiles
+    PROJECTILE(ENTITY, null),
+    ITEM_PROJECTILE(PROJECTILE, null),
+    SNOWBALL(ITEM_PROJECTILE),
+    ENDER_PEARL(ITEM_PROJECTILE),
+    EGG(ITEM_PROJECTILE),
+    EXPERIENCE_BOTTLE(ITEM_PROJECTILE),
+    FIREWORK_ROCKET(PROJECTILE),
+    LLAMA_SPIT(PROJECTILE),
+    SHULKER_BULLET(PROJECTILE),
+    FISHING_BOBBER(PROJECTILE),
+    WITHER_SKULL(PROJECTILE),
+    DRAGON_FIREBALL(PROJECTILE), // Doesn't actually inherit fireball
+
+    ABSTRACT_THROWN_POTION(ITEM_PROJECTILE, null),
+    SPLASH_POTION(ABSTRACT_THROWN_POTION),
+    LINGERING_POTION(ABSTRACT_THROWN_POTION),
+
+    ABSTRACT_ARROW(PROJECTILE, null),
+    ARROW(ABSTRACT_ARROW),
+    SPECTRAL_ARROW(ABSTRACT_ARROW),
+    TRIDENT(ABSTRACT_ARROW),
+
+    ABSTRACT_FIREBALL(ENTITY, null),
+    FIREBALL(ABSTRACT_FIREBALL),
+    SMALL_FIREBALL(ABSTRACT_FIREBALL),
+
+    ABSTRACT_WIND_CHARGE(PROJECTILE, null),
+    WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+    BREEZE_WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+
+    // Vehicles
+    VEHICLE(ENTITY, null),
+
+    ABSTRACT_MINECART(VEHICLE, null),
+    MINECART(ABSTRACT_MINECART),
+    FURNACE_MINECART(ABSTRACT_MINECART),
+    COMMAND_BLOCK_MINECART(ABSTRACT_MINECART),
+    TNT_MINECART(ABSTRACT_MINECART),
+    SPAWNER_MINECART(ABSTRACT_MINECART),
+
+    ABSTRACT_MINECART_CONTAINER(ABSTRACT_MINECART, null),
+    CHEST_MINECART(ABSTRACT_MINECART_CONTAINER),
+    HOPPER_MINECART(ABSTRACT_MINECART_CONTAINER),
+
+    ABSTRACT_BOAT(VEHICLE, null),
+    ABSTRACT_CHEST_BOAT(ABSTRACT_BOAT, null),
+    ACACIA_BOAT(ABSTRACT_BOAT),
+    ACACIA_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_CHEST_RAFT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_RAFT(ABSTRACT_BOAT),
+    BIRCH_BOAT(ABSTRACT_BOAT),
+    BIRCH_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    CHERRY_BOAT(ABSTRACT_BOAT),
+    CHERRY_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    DARK_OAK_BOAT(ABSTRACT_BOAT),
+    DARK_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    JUNGLE_BOAT(ABSTRACT_BOAT),
+    JUNGLE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    MANGROVE_BOAT(ABSTRACT_BOAT),
+    MANGROVE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    OAK_BOAT(ABSTRACT_BOAT),
+    OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    PALE_OAK_BOAT(ABSTRACT_BOAT),
+    PALE_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    SPRUCE_BOAT(ABSTRACT_BOAT),
+    SPRUCE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+
+    // Living entities as a larger subclass
+    LIVING_ENTITY(ENTITY, null),
+    ARMOR_STAND(LIVING_ENTITY),
+    PLAYER(LIVING_ENTITY),
+
+    // Mobs as a larger subclass
+    MOB(LIVING_ENTITY, null),
+    ENDER_DRAGON(MOB),
+
+    SLIME(MOB),
+    MAGMA_CUBE(SLIME),
+
+    // Ambient mobs
+    AMBIENT_CREATURE(MOB, null),
+    BAT(AMBIENT_CREATURE),
+
+    // Flying mobs
+    FLYING_MOB(MOB, null),
+    GHAST(FLYING_MOB),
+    PHANTOM(FLYING_MOB),
+
+    // Pathfinder mobs and its subclasses
+    PATHFINDER_MOB(MOB, null),
+    ALLAY(PATHFINDER_MOB),
+
+    ABSTRACT_GOLEM(PATHFINDER_MOB, null),
+    SNOW_GOLEM(ABSTRACT_GOLEM),
+    IRON_GOLEM(ABSTRACT_GOLEM),
+    SHULKER(ABSTRACT_GOLEM),
+
+    // Ageable mobs and (tamable) animals
+    ABSTRACT_AGEABLE(PATHFINDER_MOB, null),
+    ABSTRACT_VILLAGER(ABSTRACT_AGEABLE, null),
+    VILLAGER(ABSTRACT_VILLAGER),
+    WANDERING_TRADER(ABSTRACT_VILLAGER),
+
+    ABSTRACT_ANIMAL(ABSTRACT_AGEABLE, null),
+    AXOLOTL(ABSTRACT_ANIMAL),
+    CHICKEN(ABSTRACT_ANIMAL),
+    PANDA(ABSTRACT_ANIMAL),
+    PIG(ABSTRACT_ANIMAL),
+    POLAR_BEAR(ABSTRACT_ANIMAL),
+    RABBIT(ABSTRACT_ANIMAL),
+    SHEEP(ABSTRACT_ANIMAL),
+    BEE(ABSTRACT_ANIMAL),
+    TURTLE(ABSTRACT_ANIMAL),
+    FOX(ABSTRACT_ANIMAL),
+    FROG(ABSTRACT_ANIMAL),
+    GOAT(ABSTRACT_ANIMAL),
+    HOGLIN(ABSTRACT_ANIMAL),
+    STRIDER(ABSTRACT_ANIMAL),
+    SNIFFER(ABSTRACT_ANIMAL),
+    ARMADILLO(ABSTRACT_ANIMAL),
+
+    ABSTRACT_COW(ABSTRACT_ANIMAL, null),
+    COW(ABSTRACT_COW),
+    MOOSHROOM(ABSTRACT_COW),
+
+    TAMABLE_ANIMAL(ABSTRACT_ANIMAL, null),
+    CAT(TAMABLE_ANIMAL),
+    OCELOT(TAMABLE_ANIMAL),
+    WOLF(TAMABLE_ANIMAL),
+    PARROT(TAMABLE_ANIMAL),
+
+    ABSTRACT_HORSE(ABSTRACT_ANIMAL, null),
+    HORSE(ABSTRACT_HORSE),
+    SKELETON_HORSE(ABSTRACT_HORSE),
+    ZOMBIE_HORSE(ABSTRACT_HORSE),
+    CAMEL(ABSTRACT_HORSE),
+
+    ABSTRACT_CHESTED_HORSE(ABSTRACT_HORSE, null),
+    DONKEY(ABSTRACT_CHESTED_HORSE),
+    MULE(ABSTRACT_CHESTED_HORSE),
+    LLAMA(ABSTRACT_CHESTED_HORSE),
+    TRADER_LLAMA(LLAMA),
+
+    // Monsters
+    ABSTRACT_MONSTER(PATHFINDER_MOB, null),
+    BLAZE(ABSTRACT_MONSTER),
+    CREEPER(ABSTRACT_MONSTER),
+    ENDERMITE(ABSTRACT_MONSTER),
+    ENDERMAN(ABSTRACT_MONSTER),
+    GIANT(ABSTRACT_MONSTER),
+    SILVERFISH(ABSTRACT_MONSTER),
+    VEX(ABSTRACT_MONSTER),
+    WITHER(ABSTRACT_MONSTER),
+    BREEZE(ABSTRACT_MONSTER),
+    ZOGLIN(ABSTRACT_MONSTER),
+    WARDEN(ABSTRACT_MONSTER),
+    CREAKING(ABSTRACT_MONSTER),
+
+    ABSTRACT_SKELETON(ABSTRACT_MONSTER, null),
+    SKELETON(ABSTRACT_SKELETON),
+    STRAY(ABSTRACT_SKELETON),
+    WITHER_SKELETON(ABSTRACT_SKELETON),
+    BOGGED(ABSTRACT_SKELETON),
+
+    ZOMBIE(ABSTRACT_MONSTER),
+    DROWNED(ZOMBIE),
+    HUSK(ZOMBIE),
+    ZOMBIFIED_PIGLIN(ZOMBIE),
+    ZOMBIE_VILLAGER(ZOMBIE),
+
+    GUARDIAN(ABSTRACT_MONSTER),
+    ELDER_GUARDIAN(GUARDIAN),
+
+    SPIDER(ABSTRACT_MONSTER),
+    CAVE_SPIDER(SPIDER),
+
+    ABSTRACT_PIGLIN(ABSTRACT_MONSTER, null),
+    PIGLIN(ABSTRACT_PIGLIN),
+    PIGLIN_BRUTE(ABSTRACT_PIGLIN),
+
+    // Water mobs
+    AGEABLE_WATER_CREATURE(ABSTRACT_AGEABLE, null),
+    DOLPHIN(AGEABLE_WATER_CREATURE),
+
+    SQUID(AGEABLE_WATER_CREATURE),
+    GLOW_SQUID(SQUID),
+
+    WATER_ANIMAL(PATHFINDER_MOB, null),
+    ABSTRACT_FISH(WATER_ANIMAL, null),
+    PUFFERFISH(ABSTRACT_FISH),
+    TADPOLE(ABSTRACT_FISH),
+
+    ABSTRACT_SCHOOLING_FISH(ABSTRACT_FISH, null),
+    COD(ABSTRACT_SCHOOLING_FISH),
+    SALMON(ABSTRACT_SCHOOLING_FISH),
+    TROPICAL_FISH(ABSTRACT_SCHOOLING_FISH),
+
+    // Raiders
+    ABSTRACT_RAIDER(ABSTRACT_MONSTER, null),
+    WITCH(ABSTRACT_RAIDER),
+    RAVAGER(ABSTRACT_RAIDER),
+
+    ABSTRACT_ILLAGER(ABSTRACT_RAIDER, null),
+    SPELLCASTER_ILLAGER(ABSTRACT_ILLAGER, null),
+    VINDICATOR(ABSTRACT_ILLAGER),
+    PILLAGER(ABSTRACT_ILLAGER),
+    EVOKER(SPELLCASTER_ILLAGER),
+    ILLUSIONER(SPELLCASTER_ILLAGER);
+
+    private static final EntityType[] TYPES = EntityTypeUtil.createSizedArray(values());
+    private final EntityType parent;
+    private final String identifier;
+    private int id = -1;
+
+    EntityTypes1_21_5(final EntityType parent) {
+        this.parent = parent;
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
+    }
+
+    EntityTypes1_21_5(final EntityType parent, @Nullable final String identifier) {
+        this.parent = parent;
+        this.identifier = identifier;
+    }
+
+    @Override
+    public int getId() {
+        if (id == -1) {
+            throw new IllegalStateException("Ids have not been initialized yet (type " + name() + ")");
+        }
+        return id;
+    }
+
+    @Override
+    public String identifier() {
+        Preconditions.checkArgument(identifier != null, "Called identifier method on abstract type");
+        return identifier;
+    }
+
+    @Override
+    public @Nullable EntityType getParent() {
+        return parent;
+    }
+
+    @Override
+    public boolean isAbstractType() {
+        return identifier == null;
+    }
+
+    public static EntityType getTypeFromId(final int typeId) {
+        return EntityTypeUtil.getTypeFromId(TYPES, typeId, PIG);
+    }
+
+    public static void initialize(final Protocol<?, ?, ?, ?> protocol) {
+        EntityTypeUtil.initialize(values(), TYPES, protocol, (type, id) -> type.id = id);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_21_6.java

@@ -0,0 +1,318 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.entities;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.util.EntityTypeUtil;
+import com.viaversion.viaversion.util.Key;
+import java.util.Locale;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public enum EntityTypes1_21_6 implements EntityType {
+
+    ENTITY(null, null),
+
+    AREA_EFFECT_CLOUD(ENTITY),
+    END_CRYSTAL(ENTITY),
+    EVOKER_FANGS(ENTITY),
+    EXPERIENCE_ORB(ENTITY),
+    EYE_OF_ENDER(ENTITY),
+    FALLING_BLOCK(ENTITY),
+    ITEM(ENTITY),
+    TNT(ENTITY),
+    OMINOUS_ITEM_SPAWNER(ENTITY),
+    MARKER(ENTITY),
+    LIGHTNING_BOLT(ENTITY),
+    INTERACTION(ENTITY),
+
+    DISPLAY(ENTITY, null),
+    BLOCK_DISPLAY(DISPLAY),
+    ITEM_DISPLAY(DISPLAY),
+    TEXT_DISPLAY(DISPLAY),
+
+    // Hanging entities
+    HANGING_ENTITY(ENTITY, null),
+    LEASH_KNOT(HANGING_ENTITY),
+    PAINTING(HANGING_ENTITY),
+    ITEM_FRAME(HANGING_ENTITY),
+    GLOW_ITEM_FRAME(ITEM_FRAME),
+
+    // Projectiles
+    PROJECTILE(ENTITY, null),
+    ITEM_PROJECTILE(PROJECTILE, null),
+    SNOWBALL(ITEM_PROJECTILE),
+    ENDER_PEARL(ITEM_PROJECTILE),
+    EGG(ITEM_PROJECTILE),
+    EXPERIENCE_BOTTLE(ITEM_PROJECTILE),
+    FIREWORK_ROCKET(PROJECTILE),
+    LLAMA_SPIT(PROJECTILE),
+    SHULKER_BULLET(PROJECTILE),
+    FISHING_BOBBER(PROJECTILE),
+    WITHER_SKULL(PROJECTILE),
+    DRAGON_FIREBALL(PROJECTILE), // Doesn't actually inherit fireball
+
+    ABSTRACT_THROWN_POTION(ITEM_PROJECTILE, null),
+    SPLASH_POTION(ABSTRACT_THROWN_POTION),
+    LINGERING_POTION(ABSTRACT_THROWN_POTION),
+
+    ABSTRACT_ARROW(PROJECTILE, null),
+    ARROW(ABSTRACT_ARROW),
+    SPECTRAL_ARROW(ABSTRACT_ARROW),
+    TRIDENT(ABSTRACT_ARROW),
+
+    ABSTRACT_FIREBALL(ENTITY, null),
+    FIREBALL(ABSTRACT_FIREBALL),
+    SMALL_FIREBALL(ABSTRACT_FIREBALL),
+
+    ABSTRACT_WIND_CHARGE(PROJECTILE, null),
+    WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+    BREEZE_WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+
+    // Vehicles
+    VEHICLE(ENTITY, null),
+
+    ABSTRACT_MINECART(VEHICLE, null),
+    MINECART(ABSTRACT_MINECART),
+    FURNACE_MINECART(ABSTRACT_MINECART),
+    COMMAND_BLOCK_MINECART(ABSTRACT_MINECART),
+    TNT_MINECART(ABSTRACT_MINECART),
+    SPAWNER_MINECART(ABSTRACT_MINECART),
+
+    ABSTRACT_MINECART_CONTAINER(ABSTRACT_MINECART, null),
+    CHEST_MINECART(ABSTRACT_MINECART_CONTAINER),
+    HOPPER_MINECART(ABSTRACT_MINECART_CONTAINER),
+
+    ABSTRACT_BOAT(VEHICLE, null),
+    ABSTRACT_CHEST_BOAT(ABSTRACT_BOAT, null),
+    ACACIA_BOAT(ABSTRACT_BOAT),
+    ACACIA_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_CHEST_RAFT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_RAFT(ABSTRACT_BOAT),
+    BIRCH_BOAT(ABSTRACT_BOAT),
+    BIRCH_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    CHERRY_BOAT(ABSTRACT_BOAT),
+    CHERRY_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    DARK_OAK_BOAT(ABSTRACT_BOAT),
+    DARK_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    JUNGLE_BOAT(ABSTRACT_BOAT),
+    JUNGLE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    MANGROVE_BOAT(ABSTRACT_BOAT),
+    MANGROVE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    OAK_BOAT(ABSTRACT_BOAT),
+    OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    PALE_OAK_BOAT(ABSTRACT_BOAT),
+    PALE_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    SPRUCE_BOAT(ABSTRACT_BOAT),
+    SPRUCE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+
+    // Living entities as a larger subclass
+    LIVING_ENTITY(ENTITY, null),
+    ARMOR_STAND(LIVING_ENTITY),
+    PLAYER(LIVING_ENTITY),
+
+    // Mobs as a larger subclass
+    MOB(LIVING_ENTITY, null),
+    ENDER_DRAGON(MOB),
+
+    SLIME(MOB),
+    MAGMA_CUBE(SLIME),
+
+    // Ambient mobs
+    AMBIENT_CREATURE(MOB, null),
+    BAT(AMBIENT_CREATURE),
+
+    // Flying mobs
+    FLYING_MOB(MOB, null),
+    GHAST(FLYING_MOB),
+    PHANTOM(FLYING_MOB),
+
+    // Pathfinder mobs and its subclasses
+    PATHFINDER_MOB(MOB, null),
+    ALLAY(PATHFINDER_MOB),
+
+    ABSTRACT_GOLEM(PATHFINDER_MOB, null),
+    SNOW_GOLEM(ABSTRACT_GOLEM),
+    IRON_GOLEM(ABSTRACT_GOLEM),
+    SHULKER(ABSTRACT_GOLEM),
+
+    // Ageable mobs and (tamable) animals
+    ABSTRACT_AGEABLE(PATHFINDER_MOB, null),
+    ABSTRACT_VILLAGER(ABSTRACT_AGEABLE, null),
+    VILLAGER(ABSTRACT_VILLAGER),
+    WANDERING_TRADER(ABSTRACT_VILLAGER),
+
+    ABSTRACT_ANIMAL(ABSTRACT_AGEABLE, null),
+    AXOLOTL(ABSTRACT_ANIMAL),
+    CHICKEN(ABSTRACT_ANIMAL),
+    PANDA(ABSTRACT_ANIMAL),
+    PIG(ABSTRACT_ANIMAL),
+    POLAR_BEAR(ABSTRACT_ANIMAL),
+    RABBIT(ABSTRACT_ANIMAL),
+    SHEEP(ABSTRACT_ANIMAL),
+    BEE(ABSTRACT_ANIMAL),
+    TURTLE(ABSTRACT_ANIMAL),
+    FOX(ABSTRACT_ANIMAL),
+    FROG(ABSTRACT_ANIMAL),
+    GOAT(ABSTRACT_ANIMAL),
+    HOGLIN(ABSTRACT_ANIMAL),
+    STRIDER(ABSTRACT_ANIMAL),
+    SNIFFER(ABSTRACT_ANIMAL),
+    ARMADILLO(ABSTRACT_ANIMAL),
+    HAPPY_GHAST(ABSTRACT_ANIMAL),
+
+    ABSTRACT_COW(ABSTRACT_ANIMAL, null),
+    COW(ABSTRACT_COW),
+    MOOSHROOM(ABSTRACT_COW),
+
+    TAMABLE_ANIMAL(ABSTRACT_ANIMAL, null),
+    CAT(TAMABLE_ANIMAL),
+    OCELOT(TAMABLE_ANIMAL),
+    WOLF(TAMABLE_ANIMAL),
+    PARROT(TAMABLE_ANIMAL),
+
+    ABSTRACT_HORSE(ABSTRACT_ANIMAL, null),
+    HORSE(ABSTRACT_HORSE),
+    SKELETON_HORSE(ABSTRACT_HORSE),
+    ZOMBIE_HORSE(ABSTRACT_HORSE),
+    CAMEL(ABSTRACT_HORSE),
+
+    ABSTRACT_CHESTED_HORSE(ABSTRACT_HORSE, null),
+    DONKEY(ABSTRACT_CHESTED_HORSE),
+    MULE(ABSTRACT_CHESTED_HORSE),
+    LLAMA(ABSTRACT_CHESTED_HORSE),
+    TRADER_LLAMA(LLAMA),
+
+    // Monsters
+    ABSTRACT_MONSTER(PATHFINDER_MOB, null),
+    BLAZE(ABSTRACT_MONSTER),
+    CREEPER(ABSTRACT_MONSTER),
+    ENDERMITE(ABSTRACT_MONSTER),
+    ENDERMAN(ABSTRACT_MONSTER),
+    GIANT(ABSTRACT_MONSTER),
+    SILVERFISH(ABSTRACT_MONSTER),
+    VEX(ABSTRACT_MONSTER),
+    WITHER(ABSTRACT_MONSTER),
+    BREEZE(ABSTRACT_MONSTER),
+    ZOGLIN(ABSTRACT_MONSTER),
+    WARDEN(ABSTRACT_MONSTER),
+    CREAKING(ABSTRACT_MONSTER),
+
+    ABSTRACT_SKELETON(ABSTRACT_MONSTER, null),
+    SKELETON(ABSTRACT_SKELETON),
+    STRAY(ABSTRACT_SKELETON),
+    WITHER_SKELETON(ABSTRACT_SKELETON),
+    BOGGED(ABSTRACT_SKELETON),
+
+    ZOMBIE(ABSTRACT_MONSTER),
+    DROWNED(ZOMBIE),
+    HUSK(ZOMBIE),
+    ZOMBIFIED_PIGLIN(ZOMBIE),
+    ZOMBIE_VILLAGER(ZOMBIE),
+
+    GUARDIAN(ABSTRACT_MONSTER),
+    ELDER_GUARDIAN(GUARDIAN),
+
+    SPIDER(ABSTRACT_MONSTER),
+    CAVE_SPIDER(SPIDER),
+
+    ABSTRACT_PIGLIN(ABSTRACT_MONSTER, null),
+    PIGLIN(ABSTRACT_PIGLIN),
+    PIGLIN_BRUTE(ABSTRACT_PIGLIN),
+
+    // Water mobs
+    AGEABLE_WATER_CREATURE(ABSTRACT_AGEABLE, null),
+    DOLPHIN(AGEABLE_WATER_CREATURE),
+
+    SQUID(AGEABLE_WATER_CREATURE),
+    GLOW_SQUID(SQUID),
+
+    WATER_ANIMAL(PATHFINDER_MOB, null),
+    ABSTRACT_FISH(WATER_ANIMAL, null),
+    PUFFERFISH(ABSTRACT_FISH),
+    TADPOLE(ABSTRACT_FISH),
+
+    ABSTRACT_SCHOOLING_FISH(ABSTRACT_FISH, null),
+    COD(ABSTRACT_SCHOOLING_FISH),
+    SALMON(ABSTRACT_SCHOOLING_FISH),
+    TROPICAL_FISH(ABSTRACT_SCHOOLING_FISH),
+
+    // Raiders
+    ABSTRACT_RAIDER(ABSTRACT_MONSTER, null),
+    WITCH(ABSTRACT_RAIDER),
+    RAVAGER(ABSTRACT_RAIDER),
+
+    ABSTRACT_ILLAGER(ABSTRACT_RAIDER, null),
+    SPELLCASTER_ILLAGER(ABSTRACT_ILLAGER, null),
+    VINDICATOR(ABSTRACT_ILLAGER),
+    PILLAGER(ABSTRACT_ILLAGER),
+    EVOKER(SPELLCASTER_ILLAGER),
+    ILLUSIONER(SPELLCASTER_ILLAGER);
+
+    private static final EntityType[] TYPES = EntityTypeUtil.createSizedArray(values());
+    private final EntityType parent;
+    private final String identifier;
+    private int id = -1;
+
+    EntityTypes1_21_6(final EntityType parent) {
+        this.parent = parent;
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
+    }
+
+    EntityTypes1_21_6(final EntityType parent, @Nullable final String identifier) {
+        this.parent = parent;
+        this.identifier = identifier;
+    }
+
+    @Override
+    public int getId() {
+        if (id == -1) {
+            throw new IllegalStateException("Ids have not been initialized yet (type " + name() + ")");
+        }
+        return id;
+    }
+
+    @Override
+    public String identifier() {
+        Preconditions.checkArgument(identifier != null, "Called identifier method on abstract type");
+        return identifier;
+    }
+
+    @Override
+    public @Nullable EntityType getParent() {
+        return parent;
+    }
+
+    @Override
+    public boolean isAbstractType() {
+        return identifier == null;
+    }
+
+    public static EntityType getTypeFromId(final int typeId) {
+        return EntityTypeUtil.getTypeFromId(TYPES, typeId, PIG);
+    }
+
+    public static void initialize(final Protocol<?, ?, ?, ?> protocol) {
+        EntityTypeUtil.initialize(values(), TYPES, protocol, (type, id) -> type.id = id);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_21_9.java

@@ -0,0 +1,323 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.entities;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.util.EntityTypeUtil;
+import com.viaversion.viaversion.util.Key;
+import java.util.Locale;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public enum EntityTypes1_21_9 implements EntityType {
+
+    ENTITY(null, null),
+
+    AREA_EFFECT_CLOUD(ENTITY),
+    END_CRYSTAL(ENTITY),
+    EVOKER_FANGS(ENTITY),
+    EXPERIENCE_ORB(ENTITY),
+    EYE_OF_ENDER(ENTITY),
+    FALLING_BLOCK(ENTITY),
+    ITEM(ENTITY),
+    TNT(ENTITY),
+    OMINOUS_ITEM_SPAWNER(ENTITY),
+    MARKER(ENTITY),
+    LIGHTNING_BOLT(ENTITY),
+    INTERACTION(ENTITY),
+
+    DISPLAY(ENTITY, null),
+    BLOCK_DISPLAY(DISPLAY),
+    ITEM_DISPLAY(DISPLAY),
+    TEXT_DISPLAY(DISPLAY),
+
+    // Hanging entities
+    HANGING_ENTITY(ENTITY, null),
+    LEASH_KNOT(HANGING_ENTITY),
+    PAINTING(HANGING_ENTITY),
+    ITEM_FRAME(HANGING_ENTITY),
+    GLOW_ITEM_FRAME(ITEM_FRAME),
+
+    // Projectiles
+    PROJECTILE(ENTITY, null),
+    ITEM_PROJECTILE(PROJECTILE, null),
+    SNOWBALL(ITEM_PROJECTILE),
+    ENDER_PEARL(ITEM_PROJECTILE),
+    EGG(ITEM_PROJECTILE),
+    EXPERIENCE_BOTTLE(ITEM_PROJECTILE),
+    FIREWORK_ROCKET(PROJECTILE),
+    LLAMA_SPIT(PROJECTILE),
+    SHULKER_BULLET(PROJECTILE),
+    FISHING_BOBBER(PROJECTILE),
+    WITHER_SKULL(PROJECTILE),
+    DRAGON_FIREBALL(PROJECTILE), // Doesn't actually inherit fireball
+
+    ABSTRACT_THROWN_POTION(ITEM_PROJECTILE, null),
+    SPLASH_POTION(ABSTRACT_THROWN_POTION),
+    LINGERING_POTION(ABSTRACT_THROWN_POTION),
+
+    ABSTRACT_ARROW(PROJECTILE, null),
+    ARROW(ABSTRACT_ARROW),
+    SPECTRAL_ARROW(ABSTRACT_ARROW),
+    TRIDENT(ABSTRACT_ARROW),
+
+    ABSTRACT_FIREBALL(ENTITY, null),
+    FIREBALL(ABSTRACT_FIREBALL),
+    SMALL_FIREBALL(ABSTRACT_FIREBALL),
+
+    ABSTRACT_WIND_CHARGE(PROJECTILE, null),
+    WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+    BREEZE_WIND_CHARGE(ABSTRACT_WIND_CHARGE),
+
+    // Vehicles
+    VEHICLE(ENTITY, null),
+
+    ABSTRACT_MINECART(VEHICLE, null),
+    MINECART(ABSTRACT_MINECART),
+    FURNACE_MINECART(ABSTRACT_MINECART),
+    COMMAND_BLOCK_MINECART(ABSTRACT_MINECART),
+    TNT_MINECART(ABSTRACT_MINECART),
+    SPAWNER_MINECART(ABSTRACT_MINECART),
+
+    ABSTRACT_MINECART_CONTAINER(ABSTRACT_MINECART, null),
+    CHEST_MINECART(ABSTRACT_MINECART_CONTAINER),
+    HOPPER_MINECART(ABSTRACT_MINECART_CONTAINER),
+
+    ABSTRACT_BOAT(VEHICLE, null),
+    ABSTRACT_CHEST_BOAT(ABSTRACT_BOAT, null),
+    ACACIA_BOAT(ABSTRACT_BOAT),
+    ACACIA_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_CHEST_RAFT(ABSTRACT_CHEST_BOAT),
+    BAMBOO_RAFT(ABSTRACT_BOAT),
+    BIRCH_BOAT(ABSTRACT_BOAT),
+    BIRCH_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    CHERRY_BOAT(ABSTRACT_BOAT),
+    CHERRY_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    DARK_OAK_BOAT(ABSTRACT_BOAT),
+    DARK_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    JUNGLE_BOAT(ABSTRACT_BOAT),
+    JUNGLE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    MANGROVE_BOAT(ABSTRACT_BOAT),
+    MANGROVE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    OAK_BOAT(ABSTRACT_BOAT),
+    OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    PALE_OAK_BOAT(ABSTRACT_BOAT),
+    PALE_OAK_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+    SPRUCE_BOAT(ABSTRACT_BOAT),
+    SPRUCE_CHEST_BOAT(ABSTRACT_CHEST_BOAT),
+
+    // Living entities as a larger subclass
+    LIVING_ENTITY(ENTITY, null),
+    ARMOR_STAND(LIVING_ENTITY),
+
+    // Players
+    AVATAR(LIVING_ENTITY, null),
+    MANNEQUIN(AVATAR),
+    PLAYER(AVATAR),
+
+    // Mobs as a larger subclass
+    MOB(LIVING_ENTITY, null),
+    ENDER_DRAGON(MOB),
+
+    SLIME(MOB),
+    MAGMA_CUBE(SLIME),
+
+    // Ambient mobs
+    AMBIENT_CREATURE(MOB, null),
+    BAT(AMBIENT_CREATURE),
+
+    // Flying mobs
+    FLYING_MOB(MOB, null),
+    GHAST(FLYING_MOB),
+    PHANTOM(FLYING_MOB),
+
+    // Pathfinder mobs and its subclasses
+    PATHFINDER_MOB(MOB, null),
+    ALLAY(PATHFINDER_MOB),
+
+    ABSTRACT_GOLEM(PATHFINDER_MOB, null),
+    SNOW_GOLEM(ABSTRACT_GOLEM),
+    IRON_GOLEM(ABSTRACT_GOLEM),
+    SHULKER(ABSTRACT_GOLEM),
+    COPPER_GOLEM(ABSTRACT_GOLEM),
+
+    // Ageable mobs and (tamable) animals
+    ABSTRACT_AGEABLE(PATHFINDER_MOB, null),
+    ABSTRACT_VILLAGER(ABSTRACT_AGEABLE, null),
+    VILLAGER(ABSTRACT_VILLAGER),
+    WANDERING_TRADER(ABSTRACT_VILLAGER),
+
+    ABSTRACT_ANIMAL(ABSTRACT_AGEABLE, null),
+    AXOLOTL(ABSTRACT_ANIMAL),
+    CHICKEN(ABSTRACT_ANIMAL),
+    PANDA(ABSTRACT_ANIMAL),
+    PIG(ABSTRACT_ANIMAL),
+    POLAR_BEAR(ABSTRACT_ANIMAL),
+    RABBIT(ABSTRACT_ANIMAL),
+    SHEEP(ABSTRACT_ANIMAL),
+    BEE(ABSTRACT_ANIMAL),
+    TURTLE(ABSTRACT_ANIMAL),
+    FOX(ABSTRACT_ANIMAL),
+    FROG(ABSTRACT_ANIMAL),
+    GOAT(ABSTRACT_ANIMAL),
+    HOGLIN(ABSTRACT_ANIMAL),
+    STRIDER(ABSTRACT_ANIMAL),
+    SNIFFER(ABSTRACT_ANIMAL),
+    ARMADILLO(ABSTRACT_ANIMAL),
+    HAPPY_GHAST(ABSTRACT_ANIMAL),
+
+    ABSTRACT_COW(ABSTRACT_ANIMAL, null),
+    COW(ABSTRACT_COW),
+    MOOSHROOM(ABSTRACT_COW),
+
+    TAMABLE_ANIMAL(ABSTRACT_ANIMAL, null),
+    CAT(TAMABLE_ANIMAL),
+    OCELOT(TAMABLE_ANIMAL),
+    WOLF(TAMABLE_ANIMAL),
+    PARROT(TAMABLE_ANIMAL),
+
+    ABSTRACT_HORSE(ABSTRACT_ANIMAL, null),
+    HORSE(ABSTRACT_HORSE),
+    SKELETON_HORSE(ABSTRACT_HORSE),
+    ZOMBIE_HORSE(ABSTRACT_HORSE),
+    CAMEL(ABSTRACT_HORSE),
+
+    ABSTRACT_CHESTED_HORSE(ABSTRACT_HORSE, null),
+    DONKEY(ABSTRACT_CHESTED_HORSE),
+    MULE(ABSTRACT_CHESTED_HORSE),
+    LLAMA(ABSTRACT_CHESTED_HORSE),
+    TRADER_LLAMA(LLAMA),
+
+    // Monsters
+    ABSTRACT_MONSTER(PATHFINDER_MOB, null),
+    BLAZE(ABSTRACT_MONSTER),
+    CREEPER(ABSTRACT_MONSTER),
+    ENDERMITE(ABSTRACT_MONSTER),
+    ENDERMAN(ABSTRACT_MONSTER),
+    GIANT(ABSTRACT_MONSTER),
+    SILVERFISH(ABSTRACT_MONSTER),
+    VEX(ABSTRACT_MONSTER),
+    WITHER(ABSTRACT_MONSTER),
+    BREEZE(ABSTRACT_MONSTER),
+    ZOGLIN(ABSTRACT_MONSTER),
+    WARDEN(ABSTRACT_MONSTER),
+    CREAKING(ABSTRACT_MONSTER),
+
+    ABSTRACT_SKELETON(ABSTRACT_MONSTER, null),
+    SKELETON(ABSTRACT_SKELETON),
+    STRAY(ABSTRACT_SKELETON),
+    WITHER_SKELETON(ABSTRACT_SKELETON),
+    BOGGED(ABSTRACT_SKELETON),
+
+    ZOMBIE(ABSTRACT_MONSTER),
+    DROWNED(ZOMBIE),
+    HUSK(ZOMBIE),
+    ZOMBIFIED_PIGLIN(ZOMBIE),
+    ZOMBIE_VILLAGER(ZOMBIE),
+
+    GUARDIAN(ABSTRACT_MONSTER),
+    ELDER_GUARDIAN(GUARDIAN),
+
+    SPIDER(ABSTRACT_MONSTER),
+    CAVE_SPIDER(SPIDER),
+
+    ABSTRACT_PIGLIN(ABSTRACT_MONSTER, null),
+    PIGLIN(ABSTRACT_PIGLIN),
+    PIGLIN_BRUTE(ABSTRACT_PIGLIN),
+
+    // Water mobs
+    AGEABLE_WATER_CREATURE(ABSTRACT_AGEABLE, null),
+    DOLPHIN(AGEABLE_WATER_CREATURE),
+
+    SQUID(AGEABLE_WATER_CREATURE),
+    GLOW_SQUID(SQUID),
+
+    WATER_ANIMAL(PATHFINDER_MOB, null),
+    ABSTRACT_FISH(WATER_ANIMAL, null),
+    PUFFERFISH(ABSTRACT_FISH),
+    TADPOLE(ABSTRACT_FISH),
+
+    ABSTRACT_SCHOOLING_FISH(ABSTRACT_FISH, null),
+    COD(ABSTRACT_SCHOOLING_FISH),
+    SALMON(ABSTRACT_SCHOOLING_FISH),
+    TROPICAL_FISH(ABSTRACT_SCHOOLING_FISH),
+
+    // Raiders
+    ABSTRACT_RAIDER(ABSTRACT_MONSTER, null),
+    WITCH(ABSTRACT_RAIDER),
+    RAVAGER(ABSTRACT_RAIDER),
+
+    ABSTRACT_ILLAGER(ABSTRACT_RAIDER, null),
+    SPELLCASTER_ILLAGER(ABSTRACT_ILLAGER, null),
+    VINDICATOR(ABSTRACT_ILLAGER),
+    PILLAGER(ABSTRACT_ILLAGER),
+    EVOKER(SPELLCASTER_ILLAGER),
+    ILLUSIONER(SPELLCASTER_ILLAGER);
+
+    private static final EntityType[] TYPES = EntityTypeUtil.createSizedArray(values());
+    private final EntityType parent;
+    private final String identifier;
+    private int id = -1;
+
+    EntityTypes1_21_9(final EntityType parent) {
+        this.parent = parent;
+        this.identifier = Key.namespaced(name().toLowerCase(Locale.ROOT));
+    }
+
+    EntityTypes1_21_9(final EntityType parent, @Nullable final String identifier) {
+        this.parent = parent;
+        this.identifier = identifier;
+    }
+
+    @Override
+    public int getId() {
+        if (id == -1) {
+            throw new IllegalStateException("Ids have not been initialized yet (type " + name() + ")");
+        }
+        return id;
+    }
+
+    @Override
+    public String identifier() {
+        Preconditions.checkArgument(identifier != null, "Called identifier method on abstract type");
+        return identifier;
+    }
+
+    @Override
+    public @Nullable EntityType getParent() {
+        return parent;
+    }
+
+    @Override
+    public boolean isAbstractType() {
+        return identifier == null;
+    }
+
+    public static EntityType getTypeFromId(final int typeId) {
+        return EntityTypeUtil.getTypeFromId(TYPES, typeId, PIG);
+    }
+
+    public static void initialize(final Protocol<?, ?, ?, ?> protocol) {
+        EntityTypeUtil.initialize(values(), TYPES, protocol, (type, id) -> type.id = id);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_8.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_8 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -146,7 +135,7 @@ public class EntityTypes1_8 {
         SPIDER(52, ABSTRACT_MONSTER),
         CAVE_SPIDER(59, SPIDER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -187,7 +176,9 @@ public class EntityTypes1_8 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -203,7 +194,13 @@ public class EntityTypes1_8 {
     public enum ObjectType implements com.viaversion.viaversion.api.minecraft.entities.ObjectType {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -223,19 +220,25 @@ public class EntityTypes1_8 {
         ARMOR_STAND(78, EntityType.ARMOR_STAND),
         FISHIHNG_HOOK(90, EntityType.FISHING_HOOK);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -244,20 +247,28 @@ public class EntityTypes1_8 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/EntityTypes1_9.java

@@ -22,22 +22,11 @@
  */
 package com.viaversion.viaversion.api.minecraft.entities;
 
-import java.util.HashMap;
-import java.util.Map;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
 public class EntityTypes1_9 {
 
-    public static EntityType getTypeFromId(final int typeId, final boolean object) {
-        EntityType type;
-
-        if (object) {
-            type = ObjectType.getEntityType(typeId);
-        } else {
-            type = EntityType.findById(typeId);
-        }
-        return type;
-    }
-
     public enum EntityType implements com.viaversion.viaversion.api.minecraft.entities.EntityType {
 
         ENTITY,
@@ -153,7 +142,7 @@ public class EntityTypes1_9 {
         SPIDER(52, ABSTRACT_MONSTER),
         CAVE_SPIDER(59, SPIDER);
 
-        private static final Map<Integer, EntityType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<EntityType> TYPES;
 
         private final int id;
         private final EntityType parent;
@@ -194,7 +183,9 @@ public class EntityTypes1_9 {
         }
 
         static {
-            for (EntityType type : EntityType.values()) {
+            final EntityType[] values = EntityType.values();
+            TYPES = new Int2ObjectOpenHashMap<>(values.length);
+            for (EntityType type : values) {
                 TYPES.put(type.id, type);
             }
         }
@@ -211,7 +202,13 @@ public class EntityTypes1_9 {
         BOAT(1, EntityType.BOAT),
         ITEM(2, EntityType.ITEM),
         AREA_EFFECT_CLOUD(3, EntityType.AREA_EFFECT_CLOUD),
-        MINECART(10, EntityType.MINECART), // There are multiple types, but we don't need them
+        MINECART(10, EntityType.MINECART),
+        CHEST_MINECART(10, 1, EntityType.CHEST_MINECART),
+        FURNACE_MINECART(10, 2, EntityType.FURNACE_MINECART),
+        TNT_MINECART(10, 3, EntityType.TNT_MINECART),
+        SPAWNER_MINECART(10, 4, EntityType.SPAWNER_MINECART),
+        HOPPER_MINECART(10, 5, EntityType.HOPPER_MINECART),
+        COMMAND_BLOCK_MINECART(10, 6, EntityType.COMMAND_BLOCK_MINECART),
         TNT_PRIMED(50, EntityType.TNT),
         ENDER_CRYSTAL(51, EntityType.END_CRYSTAL),
         TIPPED_ARROW(60, EntityType.ARROW),
@@ -234,19 +231,25 @@ public class EntityTypes1_9 {
         SPECTRAL_ARROW(91, EntityType.SPECTRAL_ARROW),
         DRAGON_FIREBALL(93, EntityType.DRAGON_FIREBALL);
 
-        private static final Map<Integer, ObjectType> TYPES = new HashMap<>();
+        private static final Int2ObjectMap<Int2ObjectMap<ObjectType>> TYPES = new Int2ObjectOpenHashMap<>();
 
         private final int id;
+        private final int data;
         private final EntityType type;
 
         static {
             for (ObjectType type : ObjectType.values()) {
-                TYPES.put(type.id, type);
+                TYPES.computeIfAbsent(type.id, k -> new Int2ObjectOpenHashMap<>()).put(type.data, type);
             }
         }
 
         ObjectType(int id, EntityType type) {
+            this(id, 0, type);
+        }
+
+        ObjectType(int id, int data, EntityType type) {
             this.id = id;
+            this.data = data;
             this.type = type;
         }
 
@@ -255,20 +258,28 @@ public class EntityTypes1_9 {
             return id;
         }
 
+        @Override
+        public int getData() {
+            return data;
+        }
+
         @Override
         public EntityType getType() {
             return type;
         }
 
-        public static ObjectType findById(final int id) {
-            if (id == -1) {
+        public static ObjectType findById(final int id, final int data) {
+            final Int2ObjectMap<ObjectType> types = TYPES.get(id);
+            if (types == null) {
                 return null;
             }
-            return TYPES.get(id);
+
+            final ObjectType type = types.get(data);
+            return type != null ? type : types.get(0);
         }
 
-        public static EntityType getEntityType(final int id) {
-            final ObjectType objectType = findById(id);
+        public static EntityType getEntityType(final int id, final int data) {
+            final ObjectType objectType = findById(id, data);
             return objectType != null ? objectType.type : null;
         }
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entities/ObjectType.java

@@ -29,5 +29,7 @@ public interface ObjectType {
 
     int getId();
 
+    int getData();
+
     EntityType getType();
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_20_5.java

@@ -22,12 +22,9 @@
  */
 package com.viaversion.viaversion.api.minecraft.entitydata.types;
 
-import com.viaversion.viaversion.api.minecraft.Particle;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityDataType;
 import com.viaversion.viaversion.api.type.Types;
-import com.viaversion.viaversion.api.type.types.ArrayType;
-import com.viaversion.viaversion.api.type.types.misc.ParticleType;
-import com.viaversion.viaversion.api.type.types.version.Types1_20_5;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
 
 public final class EntityDataTypes1_20_5 extends AbstractEntityDataTypes {
 
@@ -38,7 +35,7 @@ public final class EntityDataTypes1_20_5 extends AbstractEntityDataTypes {
     public final EntityDataType stringType = add(4, Types.STRING);
     public final EntityDataType componentType = add(5, Types.TAG);
     public final EntityDataType optionalComponentType = add(6, Types.OPTIONAL_TAG);
-    public final EntityDataType itemType = add(7, Types1_20_5.ITEM);
+    public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);
     public final EntityDataType blockPositionType = add(10, Types.BLOCK_POSITION1_14);
@@ -63,9 +60,10 @@ public final class EntityDataTypes1_20_5 extends AbstractEntityDataTypes {
     public final EntityDataType vector3FType = add(29, Types.VECTOR3F);
     public final EntityDataType quaternionType = add(30, Types.QUATERNION);
 
-    public EntityDataTypes1_20_5(final ParticleType particleType, final ArrayType<Particle> particlesType) {
+    public EntityDataTypes1_20_5(final VersionedTypesHolder types) {
         super(31);
-        this.particleType = add(17, particleType);
-        this.particlesType = add(18, particlesType);
+        this.itemType = add(7, types.item());
+        this.particleType = add(17, types.particle());
+        this.particlesType = add(18, types.particles());
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_21.java

@@ -23,14 +23,10 @@
 package com.viaversion.viaversion.api.minecraft.entitydata.types;
 
 import com.viaversion.viaversion.api.minecraft.PaintingVariant;
-import com.viaversion.viaversion.api.minecraft.Particle;
 import com.viaversion.viaversion.api.minecraft.WolfVariant;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityDataType;
-import com.viaversion.viaversion.api.minecraft.item.Item;
-import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
-import com.viaversion.viaversion.api.type.types.ArrayType;
-import com.viaversion.viaversion.api.type.types.misc.ParticleType;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
 
 public final class EntityDataTypes1_21 extends AbstractEntityDataTypes {
 
@@ -66,10 +62,10 @@ public final class EntityDataTypes1_21 extends AbstractEntityDataTypes {
     public final EntityDataType vector3FType = add(29, Types.VECTOR3F);
     public final EntityDataType quaternionType = add(30, Types.QUATERNION);
 
-    public EntityDataTypes1_21(final Type<Item> itemType, final ParticleType particleType, final ArrayType<Particle> particlesType) {
+    public EntityDataTypes1_21(final VersionedTypesHolder types) {
         super(31);
-        this.itemType = add(7, itemType);
-        this.particleType = add(17, particleType);
-        this.particlesType = add(18, particlesType);
+        this.itemType = add(7, types.item());
+        this.particleType = add(17, types.particle());
+        this.particlesType = add(18, types.particles());
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_21_2.java

@@ -23,13 +23,10 @@
 package com.viaversion.viaversion.api.minecraft.entitydata.types;
 
 import com.viaversion.viaversion.api.minecraft.PaintingVariant;
-import com.viaversion.viaversion.api.minecraft.Particle;
 import com.viaversion.viaversion.api.minecraft.WolfVariant;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityDataType;
-import com.viaversion.viaversion.api.minecraft.item.Item;
-import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
-import com.viaversion.viaversion.api.type.types.misc.ParticleType;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
 
 public final class EntityDataTypes1_21_2 extends AbstractEntityDataTypes {
 
@@ -65,10 +62,10 @@ public final class EntityDataTypes1_21_2 extends AbstractEntityDataTypes {
     public final EntityDataType vector3FType = add(29, Types.VECTOR3F);
     public final EntityDataType quaternionType = add(30, Types.QUATERNION);
 
-    public EntityDataTypes1_21_2(final Type<Item> itemType, final ParticleType particleType, final Type<Particle[]> particlesType) {
+    public EntityDataTypes1_21_2(final VersionedTypesHolder types) {
         super(31);
-        this.itemType = add(7, itemType);
-        this.particleType = add(17, particleType);
-        this.particlesType = add(18, particlesType);
+        this.itemType = add(7, types.item());
+        this.particleType = add(17, types.particle());
+        this.particlesType = add(18, types.particles());
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_21_5.java

@@ -0,0 +1,74 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.entitydata.types;
+
+import com.viaversion.viaversion.api.minecraft.PaintingVariant;
+import com.viaversion.viaversion.api.minecraft.entitydata.EntityDataType;
+import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
+
+public final class EntityDataTypes1_21_5 extends AbstractEntityDataTypes {
+
+    public final EntityDataType byteType = add(0, Types.BYTE);
+    public final EntityDataType varIntType = add(1, Types.VAR_INT);
+    public final EntityDataType longType = add(2, Types.VAR_LONG);
+    public final EntityDataType floatType = add(3, Types.FLOAT);
+    public final EntityDataType stringType = add(4, Types.STRING);
+    public final EntityDataType componentType = add(5, Types.TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.OPTIONAL_TAG);
+    public final EntityDataType itemType;
+    public final EntityDataType booleanType = add(8, Types.BOOLEAN);
+    public final EntityDataType rotationsType = add(9, Types.ROTATIONS);
+    public final EntityDataType blockPositionType = add(10, Types.BLOCK_POSITION1_14);
+    public final EntityDataType optionalBlockPositionType = add(11, Types.OPTIONAL_POSITION_1_14);
+    public final EntityDataType directionType = add(12, Types.VAR_INT);
+    public final EntityDataType optionalUUIDType = add(13, Types.OPTIONAL_UUID);
+    public final EntityDataType blockStateType = add(14, Types.VAR_INT);
+    public final EntityDataType optionalBlockStateType = add(15, Types.VAR_INT);
+    public final EntityDataType compoundTagType = add(16, Types.COMPOUND_TAG);
+    public final EntityDataType particleType;
+    public final EntityDataType particlesType;
+    public final EntityDataType villagerDatatType = add(19, Types.VILLAGER_DATA);
+    public final EntityDataType optionalVarIntType = add(20, Types.OPTIONAL_VAR_INT);
+    public final EntityDataType poseType = add(21, Types.VAR_INT);
+    public final EntityDataType catVariantType = add(22, Types.VAR_INT);
+    public final EntityDataType cowVariantType = add(23, Types.VAR_INT);
+    public final EntityDataType wolfVariantType = add(24, Types.VAR_INT);
+    public final EntityDataType wolfSoundVariantType = add(25, Types.VAR_INT);
+    public final EntityDataType frogVariantType = add(26, Types.VAR_INT);
+    public final EntityDataType pigVariantType = add(27, Types.VAR_INT);
+    public final EntityDataType chickenVariantType = add(28, Types.VAR_INT);
+    public final EntityDataType optionalGlobalPosition = add(29, Types.OPTIONAL_GLOBAL_POSITION);
+    public final EntityDataType paintingVariantType = add(30, PaintingVariant.TYPE1_21_2);
+    public final EntityDataType snifferState = add(31, Types.VAR_INT);
+    public final EntityDataType armadilloState = add(32, Types.VAR_INT);
+    public final EntityDataType vector3FType = add(33, Types.VECTOR3F);
+    public final EntityDataType quaternionType = add(34, Types.QUATERNION);
+
+    public EntityDataTypes1_21_5(final VersionedTypesHolder types) {
+        super(35);
+        this.itemType = add(7, types.item());
+        this.particleType = add(17, types.particle());
+        this.particlesType = add(18, types.particles());
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_21_9.java

@@ -0,0 +1,76 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.entitydata.types;
+
+import com.viaversion.viaversion.api.minecraft.PaintingVariant;
+import com.viaversion.viaversion.api.minecraft.entitydata.EntityDataType;
+import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.api.type.types.version.VersionedTypesHolder;
+
+public final class EntityDataTypes1_21_9 extends AbstractEntityDataTypes {
+
+    public final EntityDataType byteType = add(0, Types.BYTE);
+    public final EntityDataType varIntType = add(1, Types.VAR_INT);
+    public final EntityDataType longType = add(2, Types.VAR_LONG);
+    public final EntityDataType floatType = add(3, Types.FLOAT);
+    public final EntityDataType stringType = add(4, Types.STRING);
+    public final EntityDataType componentType = add(5, Types.TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.OPTIONAL_TAG);
+    public final EntityDataType itemType;
+    public final EntityDataType booleanType = add(8, Types.BOOLEAN);
+    public final EntityDataType rotationsType = add(9, Types.ROTATIONS);
+    public final EntityDataType blockPositionType = add(10, Types.BLOCK_POSITION1_14);
+    public final EntityDataType optionalBlockPositionType = add(11, Types.OPTIONAL_POSITION_1_14);
+    public final EntityDataType directionType = add(12, Types.VAR_INT);
+    public final EntityDataType optionalUUIDType = add(13, Types.OPTIONAL_UUID);
+    public final EntityDataType blockStateType = add(14, Types.VAR_INT);
+    public final EntityDataType optionalBlockStateType = add(15, Types.VAR_INT);
+    public final EntityDataType particleType;
+    public final EntityDataType particlesType;
+    public final EntityDataType villagerDatatType = add(18, Types.VILLAGER_DATA);
+    public final EntityDataType optionalVarIntType = add(19, Types.OPTIONAL_VAR_INT);
+    public final EntityDataType poseType = add(20, Types.VAR_INT);
+    public final EntityDataType catVariantType = add(21, Types.VAR_INT);
+    public final EntityDataType cowVariantType = add(22, Types.VAR_INT);
+    public final EntityDataType wolfVariantType = add(23, Types.VAR_INT);
+    public final EntityDataType wolfSoundVariantType = add(24, Types.VAR_INT);
+    public final EntityDataType frogVariantType = add(25, Types.VAR_INT);
+    public final EntityDataType pigVariantType = add(26, Types.VAR_INT);
+    public final EntityDataType chickenVariantType = add(27, Types.VAR_INT);
+    public final EntityDataType optionalGlobalPosition = add(28, Types.OPTIONAL_GLOBAL_POSITION);
+    public final EntityDataType paintingVariantType = add(29, PaintingVariant.TYPE1_21_2);
+    public final EntityDataType snifferState = add(30, Types.VAR_INT);
+    public final EntityDataType armadilloState = add(31, Types.VAR_INT);
+    public final EntityDataType copperGolemState = add(32, Types.VAR_INT);
+    public final EntityDataType weatheringCopperState = add(33, Types.VAR_INT);
+    public final EntityDataType vector3FType = add(34, Types.VECTOR3F);
+    public final EntityDataType quaternionType = add(35, Types.QUATERNION);
+    public final EntityDataType mannequinProfileType = add(36, Types.RESOLVABLE_PROFILE);
+
+    public EntityDataTypes1_21_9(final VersionedTypesHolder types) {
+        super(37);
+        this.itemType = add(7, types.item());
+        this.particleType = add(16, types.particle());
+        this.particlesType = add(17, types.particles());
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/HashedItem.java

@@ -0,0 +1,45 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.item;
+
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.IntSet;
+
+/**
+ * Item that does not hold any real data outside of its id and amount.
+ * Instead, it holds hashes of added data and a set of keys of removed data.
+ * <p>
+ * This stores the raw int identifiers instead of data keys to simplify handling across protocols
+ * under the assumption that the keys are almost never needed beyond automated id updating.
+ *
+ * @see Item
+ */
+public interface HashedItem extends ItemBase {
+
+    Int2IntMap dataHashesById();
+
+    IntSet removedDataIds();
+
+    @Override
+    HashedItem copy();
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/HashedStructuredItem.java

@@ -0,0 +1,115 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.item;
+
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
+import it.unimi.dsi.fastutil.ints.IntSet;
+
+public class HashedStructuredItem implements HashedItem {
+    private final Int2IntMap dataHashes;
+    private final IntSet removedData;
+    private int identifier;
+    private int amount;
+
+    public HashedStructuredItem(final int identifier, final int amount) {
+        this(identifier, amount, new Int2IntOpenHashMap(0), new IntOpenHashSet(0));
+    }
+
+    public HashedStructuredItem(final int identifier, final int amount, final Int2IntMap dataHashes, final IntSet removedData) {
+        this.identifier = identifier;
+        this.amount = amount;
+        this.dataHashes = dataHashes;
+        this.removedData = removedData;
+    }
+
+    public static HashedStructuredItem empty() {
+        // Data is mutable, create a new item
+        return new HashedStructuredItem(0, 0);
+    }
+
+    @Override
+    public int identifier() {
+        return this.identifier;
+    }
+
+    @Override
+    public void setIdentifier(final int identifier) {
+        this.identifier = identifier;
+    }
+
+    @Override
+    public int amount() {
+        return this.amount;
+    }
+
+    @Override
+    public void setAmount(final int amount) {
+        this.amount = amount;
+    }
+
+    @Override
+    public Int2IntMap dataHashesById() {
+        return this.dataHashes;
+    }
+
+    @Override
+    public IntSet removedDataIds() {
+        return this.removedData;
+    }
+
+    @Override
+    public HashedItem copy() {
+        return new HashedStructuredItem(identifier, amount, new Int2IntOpenHashMap(dataHashes), new IntOpenHashSet(removedData));
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        final HashedStructuredItem that = (HashedStructuredItem) o;
+        if (identifier != that.identifier) return false;
+        if (amount != that.amount) return false;
+        return dataHashes.equals(that.dataHashes) && removedData.equals(that.removedData);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = dataHashes.hashCode();
+        result = 31 * result + removedData.hashCode();
+        result = 31 * result + identifier;
+        result = 31 * result + amount;
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "HashedStructuredItem{" +
+            "data=Hashes" + dataHashes +
+            ", removedData=" + removedData +
+            ", identifier=" + identifier +
+            ", amount=" + amount +
+            '}';
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/Item.java

@@ -26,35 +26,7 @@ import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.viaversion.api.minecraft.data.StructuredDataContainer;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-public interface Item {
-
-    /**
-     * Returns the item identifier.
-     *
-     * @return item identifier
-     */
-    int identifier();
-
-    /**
-     * Sets the item identifier.
-     *
-     * @param identifier item identifier
-     */
-    void setIdentifier(int identifier);
-
-    /**
-     * Returns the item amount.
-     *
-     * @return item amount
-     */
-    int amount();
-
-    /**
-     * Returns the item amount.
-     *
-     * @param amount item amount
-     */
-    void setAmount(int amount);
+public interface Item extends ItemBase {
 
     /**
      * Returns the item data. Always 0 for 1.13+ items.
@@ -102,14 +74,6 @@ public interface Item {
      *
      * @return copy of the item
      */
+    @Override
     Item copy();
-
-    /**
-     * Returns true if the item is empty.
-     *
-     * @return true if the item is empty
-     */
-    default boolean isEmpty() {
-        return identifier() == 0 || amount() <= 0;
-    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/ItemBase.java

@@ -0,0 +1,72 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.item;
+
+import com.viaversion.viaversion.util.Copyable;
+
+/**
+ * @see Item
+ * @see HashedItem
+ */
+public interface ItemBase extends Copyable {
+
+    /**
+     * Returns the item identifier.
+     *
+     * @return item identifier
+     */
+    int identifier();
+
+    /**
+     * Sets the item identifier.
+     *
+     * @param identifier item identifier
+     */
+    void setIdentifier(int identifier);
+
+    /**
+     * Returns the item amount.
+     *
+     * @return item amount
+     */
+    int amount();
+
+    /**
+     * Returns the item amount.
+     *
+     * @param amount item amount
+     */
+    void setAmount(int amount);
+
+    /**
+     * Returns true if the item is empty.
+     *
+     * @return true if the item is empty
+     */
+    default boolean isEmpty() {
+        return identifier() == 0 || amount() <= 0;
+    }
+
+    @Override
+    ItemBase copy();
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/AdventureModePredicate.java

@@ -22,32 +22,68 @@
  */
 package com.viaversion.viaversion.api.minecraft.item.data;
 
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.data.StructuredData;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.util.Copyable;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
-import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 
-public record AdventureModePredicate(BlockPredicate[] predicates, boolean showInTooltip) {
+public record AdventureModePredicate(BlockPredicate[] predicates,
+                                     boolean showInTooltip) implements Copyable, Rewritable {
 
-    public static final Type<AdventureModePredicate> TYPE = new Type<>(AdventureModePredicate.class) {
+    public AdventureModePredicate(final BlockPredicate[] predicates) {
+        this(predicates, true);
+    }
+
+    public static final Type<AdventureModePredicate> TYPE1_20_5 = new Type<>(AdventureModePredicate.class) {
         @Override
         public AdventureModePredicate read(final ByteBuf buffer) {
-            final BlockPredicate[] predicates = BlockPredicate.ARRAY_TYPE.read(buffer);
+            final BlockPredicate[] predicates = BlockPredicate.ARRAY_TYPE1_20_5.read(buffer);
             final boolean showInTooltip = buffer.readBoolean();
             return new AdventureModePredicate(predicates, showInTooltip);
         }
 
         @Override
         public void write(final ByteBuf buffer, final AdventureModePredicate value) {
-            BlockPredicate.ARRAY_TYPE.write(buffer, value.predicates);
+            BlockPredicate.ARRAY_TYPE1_20_5.write(buffer, value.predicates);
             buffer.writeBoolean(value.showInTooltip);
         }
     };
 
-    public AdventureModePredicate rewrite(final Int2IntFunction blockIdRewriter) {
+    public static final class AdventureModePredicateType1_21_5 extends Type<AdventureModePredicate> {
+        private final Type<BlockPredicate[]> blockPredicateType;
+
+        public AdventureModePredicateType1_21_5(final Type<StructuredData<?>[]> dataArrayType) {
+            super(AdventureModePredicate.class);
+            this.blockPredicateType = new ArrayType<>(new BlockPredicate.BlockPredicateType1_21_5(dataArrayType));
+        }
+
+        @Override
+        public AdventureModePredicate read(final ByteBuf buffer) {
+            final BlockPredicate[] predicates = blockPredicateType.read(buffer);
+            return new AdventureModePredicate(predicates);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final AdventureModePredicate value) {
+            blockPredicateType.write(buffer, value.predicates);
+        }
+    }
+
+    @Override
+    public AdventureModePredicate rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
         final BlockPredicate[] predicates = new BlockPredicate[this.predicates.length];
         for (int i = 0; i < predicates.length; i++) {
-            predicates[i] = this.predicates[i].rewrite(blockIdRewriter);
+            predicates[i] = this.predicates[i].rewrite(connection, protocol, clientbound);
         }
         return new AdventureModePredicate(predicates, showInTooltip);
     }
+
+    @Override
+    public AdventureModePredicate copy() {
+        return new AdventureModePredicate(Copyable.copy(predicates), showInTooltip);
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/ArmorTrim.java

@@ -22,18 +22,25 @@
  */
 package com.viaversion.viaversion.api.minecraft.item.data;
 
+import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.Holder;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
-import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 
-public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPattern> pattern, boolean showInTooltip) {
+public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPattern> pattern,
+                        boolean showInTooltip) implements Rewritable {
+
+    public ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPattern> pattern) {
+        this(material, pattern, true);
+    }
 
     public static final Type<ArmorTrim> TYPE1_20_5 = new Type<>(ArmorTrim.class) {
         @Override
         public ArmorTrim read(final ByteBuf buffer) {
             final Holder<ArmorTrimMaterial> material = ArmorTrimMaterial.TYPE1_20_5.read(buffer);
-            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE.read(buffer);
+            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE1_20_5.read(buffer);
             final boolean showInTooltip = buffer.readBoolean();
             return new ArmorTrim(material, pattern, showInTooltip);
         }
@@ -41,7 +48,7 @@ public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPatt
         @Override
         public void write(final ByteBuf buffer, final ArmorTrim value) {
             ArmorTrimMaterial.TYPE1_20_5.write(buffer, value.material);
-            ArmorTrimPattern.TYPE.write(buffer, value.pattern);
+            ArmorTrimPattern.TYPE1_20_5.write(buffer, value.pattern);
             buffer.writeBoolean(value.showInTooltip);
         }
     };
@@ -49,7 +56,7 @@ public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPatt
         @Override
         public ArmorTrim read(final ByteBuf buffer) {
             final Holder<ArmorTrimMaterial> material = ArmorTrimMaterial.TYPE1_21_2.read(buffer);
-            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE.read(buffer);
+            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE1_20_5.read(buffer);
             final boolean showInTooltip = buffer.readBoolean();
             return new ArmorTrim(material, pattern, showInTooltip);
         }
@@ -57,7 +64,7 @@ public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPatt
         @Override
         public void write(final ByteBuf buffer, final ArmorTrim value) {
             ArmorTrimMaterial.TYPE1_21_2.write(buffer, value.material);
-            ArmorTrimPattern.TYPE.write(buffer, value.pattern);
+            ArmorTrimPattern.TYPE1_20_5.write(buffer, value.pattern);
             buffer.writeBoolean(value.showInTooltip);
         }
     };
@@ -65,7 +72,7 @@ public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPatt
         @Override
         public ArmorTrim read(final ByteBuf buffer) {
             final Holder<ArmorTrimMaterial> material = ArmorTrimMaterial.TYPE1_21_4.read(buffer);
-            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE.read(buffer);
+            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE1_20_5.read(buffer);
             final boolean showInTooltip = buffer.readBoolean();
             return new ArmorTrim(material, pattern, showInTooltip);
         }
@@ -73,20 +80,35 @@ public record ArmorTrim(Holder<ArmorTrimMaterial> material, Holder<ArmorTrimPatt
         @Override
         public void write(final ByteBuf buffer, final ArmorTrim value) {
             ArmorTrimMaterial.TYPE1_21_4.write(buffer, value.material);
-            ArmorTrimPattern.TYPE.write(buffer, value.pattern);
+            ArmorTrimPattern.TYPE1_20_5.write(buffer, value.pattern);
             buffer.writeBoolean(value.showInTooltip);
         }
     };
+    public static final Type<ArmorTrim> TYPE1_21_5 = new Type<>(ArmorTrim.class) {
+        @Override
+        public ArmorTrim read(final ByteBuf buffer) {
+            final Holder<ArmorTrimMaterial> material = ArmorTrimMaterial.TYPE1_21_5.read(buffer);
+            final Holder<ArmorTrimPattern> pattern = ArmorTrimPattern.TYPE1_21_5.read(buffer);
+            return new ArmorTrim(material, pattern);
+        }
 
-    public ArmorTrim rewrite(final Int2IntFunction idRewriteFunction) {
+        @Override
+        public void write(final ByteBuf buffer, final ArmorTrim value) {
+            ArmorTrimMaterial.TYPE1_21_5.write(buffer, value.material);
+            ArmorTrimPattern.TYPE1_21_5.write(buffer, value.pattern);
+        }
+    };
+
+    @Override
+    public ArmorTrim rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
         Holder<ArmorTrimMaterial> material = this.material;
         if (material.isDirect()) {
-            material = Holder.of(material.value().rewrite(idRewriteFunction));
+            material = Holder.of(material.value().rewrite(connection, protocol, clientbound));
         }
 
         Holder<ArmorTrimPattern> pattern = this.pattern;
         if (pattern.isDirect()) {
-            pattern = Holder.of(pattern.value().rewrite(idRewriteFunction));
+            pattern = Holder.of(pattern.value().rewrite(connection, protocol, clientbound));
         }
         return new ArmorTrim(material, pattern, showInTooltip);
     }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/ArmorTrimMaterial.java

@@ -23,20 +23,28 @@
 package com.viaversion.viaversion.api.minecraft.item.data;
 
 import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.misc.HolderType;
+import com.viaversion.viaversion.util.Copyable;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
-import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 import it.unimi.dsi.fastutil.objects.Object2ObjectArrayMap;
 import java.util.Map;
 
 public record ArmorTrimMaterial(String assetName, int itemId, float itemModelIndex,
-                                Map<String, String> overrideArmorMaterials, Tag description) {
+                                Map<String, String> overrideArmorMaterials,
+                                Tag description) implements Copyable, Rewritable {
 
     public ArmorTrimMaterial(final String assetName, final int itemId, final Map<String, String> overrideArmorMaterials, final Tag description) {
         this(assetName, itemId, 0F, overrideArmorMaterials, description);
     }
 
+    public ArmorTrimMaterial(final String assetName, final Map<String, String> overrideArmorMaterials, final Tag description) {
+        this(assetName, 0, 0F, overrideArmorMaterials, description);
+    }
+
     public static final HolderType<ArmorTrimMaterial> TYPE1_20_5 = new HolderType<>() {
         // The override key is an int, but given we don't use it at all and that creating a new type is annoying,
         // we'll just store it in the string map:tm:
@@ -47,7 +55,7 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             final float itemModelIndex = buffer.readFloat();
 
             final int overrideArmorMaterialsSize = Types.VAR_INT.readPrimitive(buffer);
-            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>(overrideArmorMaterialsSize);
+            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>();
             for (int i = 0; i < overrideArmorMaterialsSize; i++) {
                 final int key = Types.VAR_INT.readPrimitive(buffer);
                 final String value = Types.STRING.read(buffer);
@@ -73,7 +81,6 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             Types.TAG.write(buffer, value.description());
         }
     };
-
     public static final HolderType<ArmorTrimMaterial> TYPE1_21_2 = new HolderType<>() {
         @Override
         public ArmorTrimMaterial readDirect(final ByteBuf buffer) {
@@ -82,7 +89,7 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             final float itemModelIndex = buffer.readFloat();
 
             final int overrideArmorMaterialsSize = Types.VAR_INT.readPrimitive(buffer);
-            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>(overrideArmorMaterialsSize);
+            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>();
             for (int i = 0; i < overrideArmorMaterialsSize; i++) {
                 final String key = Types.STRING.read(buffer);
                 final String value = Types.STRING.read(buffer);
@@ -108,7 +115,6 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             Types.TAG.write(buffer, value.description());
         }
     };
-
     public static final HolderType<ArmorTrimMaterial> TYPE1_21_4 = new HolderType<>() {
         @Override
         public ArmorTrimMaterial readDirect(final ByteBuf buffer) {
@@ -116,7 +122,7 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             final int item = Types.VAR_INT.readPrimitive(buffer);
 
             final int overrideArmorMaterialsSize = Types.VAR_INT.readPrimitive(buffer);
-            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>(overrideArmorMaterialsSize);
+            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>();
             for (int i = 0; i < overrideArmorMaterialsSize; i++) {
                 final String key = Types.STRING.read(buffer);
                 final String value = Types.STRING.read(buffer);
@@ -141,8 +147,44 @@ public record ArmorTrimMaterial(String assetName, int itemId, float itemModelInd
             Types.TAG.write(buffer, value.description());
         }
     };
+    public static final HolderType<ArmorTrimMaterial> TYPE1_21_5 = new HolderType<>() {
+        @Override
+        public ArmorTrimMaterial readDirect(final ByteBuf buffer) {
+            final String assetName = Types.STRING.read(buffer);
 
-    public ArmorTrimMaterial rewrite(final Int2IntFunction idRewriteFunction) {
-        return new ArmorTrimMaterial(assetName, idRewriteFunction.applyAsInt(itemId), itemModelIndex, overrideArmorMaterials, description);
+            final int overrideArmorMaterialsSize = Types.VAR_INT.readPrimitive(buffer);
+            final Map<String, String> overrideArmorMaterials = new Object2ObjectArrayMap<>();
+            for (int i = 0; i < overrideArmorMaterialsSize; i++) {
+                final String key = Types.STRING.read(buffer);
+                final String value = Types.STRING.read(buffer);
+                overrideArmorMaterials.put(key, value);
+            }
+
+            final Tag description = Types.TAG.read(buffer);
+            return new ArmorTrimMaterial(assetName, overrideArmorMaterials, description);
+        }
+
+        @Override
+        public void writeDirect(final ByteBuf buffer, final ArmorTrimMaterial value) {
+            Types.STRING.write(buffer, value.assetName());
+
+            Types.VAR_INT.writePrimitive(buffer, value.overrideArmorMaterials().size());
+            for (final Map.Entry<String, String> entry : value.overrideArmorMaterials().entrySet()) {
+                Types.STRING.write(buffer, entry.getKey());
+                Types.STRING.write(buffer, entry.getValue());
+            }
+
+            Types.TAG.write(buffer, value.description());
+        }
+    };
+
+    @Override
+    public ArmorTrimMaterial rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
+        return new ArmorTrimMaterial(assetName, Rewritable.rewriteItem(protocol, clientbound, itemId), itemModelIndex, overrideArmorMaterials, description);
+    }
+
+    @Override
+    public ArmorTrimMaterial copy() {
+        return new ArmorTrimMaterial(assetName, itemId, itemModelIndex, new Object2ObjectArrayMap<>(overrideArmorMaterials), description);
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/ArmorTrimPattern.java

@@ -23,14 +23,21 @@
 package com.viaversion.viaversion.api.minecraft.item.data;
 
 import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.misc.HolderType;
+import com.viaversion.viaversion.util.Copyable;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
-import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 
-public record ArmorTrimPattern(String assetName, int itemId, Tag description, boolean decal) {
+public record ArmorTrimPattern(String assetName, int itemId, Tag description, boolean decal) implements Copyable, Rewritable {
 
-    public static final HolderType<ArmorTrimPattern> TYPE = new HolderType<>() {
+    public ArmorTrimPattern(final String assetName, final Tag description, final boolean decal) {
+        this(assetName, 0, description, decal);
+    }
+
+    public static final HolderType<ArmorTrimPattern> TYPE1_20_5 = new HolderType<>() {
         @Override
         public ArmorTrimPattern readDirect(final ByteBuf buffer) {
             final String assetName = Types.STRING.read(buffer);
@@ -48,8 +55,30 @@ public record ArmorTrimPattern(String assetName, int itemId, Tag description, bo
             buffer.writeBoolean(value.decal());
         }
     };
+    public static final HolderType<ArmorTrimPattern> TYPE1_21_5 = new HolderType<>() {
+        @Override
+        public ArmorTrimPattern readDirect(final ByteBuf buffer) {
+            final String assetName = Types.STRING.read(buffer);
+            final Tag description = Types.TAG.read(buffer);
+            final boolean decal = buffer.readBoolean();
+            return new ArmorTrimPattern(assetName, description, decal);
+        }
 
-    public ArmorTrimPattern rewrite(final Int2IntFunction idRewriteFunction) {
-        return new ArmorTrimPattern(assetName, idRewriteFunction.applyAsInt(itemId), description, decal);
+        @Override
+        public void writeDirect(final ByteBuf buffer, final ArmorTrimPattern value) {
+            Types.STRING.write(buffer, value.assetName());
+            Types.TAG.write(buffer, value.description());
+            buffer.writeBoolean(value.decal());
+        }
+    };
+
+    @Override
+    public ArmorTrimPattern rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
+        return new ArmorTrimPattern(assetName, Rewritable.rewriteItem(protocol, clientbound, itemId), description, decal);
+    }
+
+    @Override
+    public ArmorTrimPattern copy() {
+        return new ArmorTrimPattern(assetName, itemId, description.copy(), decal);
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/AttributeModifiers1_20_5.java

@@ -22,13 +22,21 @@
  */
 package com.viaversion.viaversion.api.minecraft.item.data;
 
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.FullMappings;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.util.Copyable;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.UUID;
 
-public record AttributeModifiers1_20_5(AttributeModifier[] modifiers, boolean showInTooltip) {
+public record AttributeModifiers1_20_5(AttributeModifier[] modifiers,
+                                       boolean showInTooltip) implements Copyable, Rewritable {
 
     public static final Type<AttributeModifiers1_20_5> TYPE = new Type<>(AttributeModifiers1_20_5.class) {
         @Override
@@ -45,6 +53,28 @@ public record AttributeModifiers1_20_5(AttributeModifier[] modifiers, boolean sh
         }
     };
 
+    @Override
+    public AttributeModifiers1_20_5 copy() {
+        return new AttributeModifiers1_20_5(Copyable.copy(modifiers), showInTooltip);
+    }
+
+    @Override
+    public AttributeModifiers1_20_5 rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
+        final FullMappings mappings = protocol.getMappingData().getAttributeMappings();
+        if (mappings == null) {
+            return this;
+        }
+
+        final List<AttributeModifier> modifiers = new ArrayList<>(this.modifiers.length);
+        for (final AttributeModifier modifier : this.modifiers) {
+            final int mappedId = clientbound ? mappings.getNewId(modifier.attribute()) : mappings.inverse().getNewId(modifier.attribute());
+            if (mappedId != -1) {
+                modifiers.add(new AttributeModifier(mappedId, modifier.modifier(), modifier.slotType()));
+            }
+        }
+        return new AttributeModifiers1_20_5(modifiers.toArray(AttributeModifier[]::new), this.showInTooltip);
+    }
+
     public record AttributeModifier(int attribute, ModifierData modifier, int slotType) {
 
         public static final Type<AttributeModifier> TYPE = new Type<>(AttributeModifier.class) {

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/AttributeModifiers1_21.java

@@ -22,41 +22,117 @@
  */
 package com.viaversion.viaversion.api.minecraft.item.data;
 
+import com.viaversion.nbt.tag.Tag;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.FullMappings;
+import com.viaversion.viaversion.api.minecraft.codec.Ops;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.util.Copyable;
+import com.viaversion.viaversion.util.Key;
+import com.viaversion.viaversion.util.Rewritable;
 import io.netty.buffer.ByteBuf;
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
+import java.util.ArrayList;
+import java.util.List;
 
-public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean showInTooltip) {
+public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean showInTooltip) implements Copyable, Rewritable {
 
-    public static final Type<AttributeModifiers1_21> TYPE = new Type<>(AttributeModifiers1_21.class) {
+    public AttributeModifiers1_21(final AttributeModifier[] modifiers) {
+        this(modifiers, true);
+    }
+
+    public static final Type<AttributeModifiers1_21> TYPE1_21 = new Type<>(AttributeModifiers1_21.class) {
         @Override
         public AttributeModifiers1_21 read(final ByteBuf buffer) {
-            final AttributeModifier[] modifiers = AttributeModifier.ARRAY_TYPE.read(buffer);
+            final AttributeModifier[] modifiers = AttributeModifier.ARRAY_TYPE1_21.read(buffer);
             final boolean showInTooltip = buffer.readBoolean();
             return new AttributeModifiers1_21(modifiers, showInTooltip);
         }
 
         @Override
         public void write(final ByteBuf buffer, final AttributeModifiers1_21 value) {
-            AttributeModifier.ARRAY_TYPE.write(buffer, value.modifiers());
+            AttributeModifier.ARRAY_TYPE1_21.write(buffer, value.modifiers());
             buffer.writeBoolean(value.showInTooltip());
         }
     };
+    public static final Type<AttributeModifiers1_21> TYPE1_21_5 = new Type<>(AttributeModifiers1_21.class) {
+        @Override
+        public AttributeModifiers1_21 read(final ByteBuf buffer) {
+            final AttributeModifier[] modifiers = AttributeModifier.ARRAY_TYPE1_21.read(buffer);
+            return new AttributeModifiers1_21(modifiers);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final AttributeModifiers1_21 value) {
+            AttributeModifier.ARRAY_TYPE1_21.write(buffer, value.modifiers());
+        }
+
+        @Override
+        public void write(final Ops ops, final AttributeModifiers1_21 value) {
+            ops.write(AttributeModifier.ARRAY_TYPE1_21, value.modifiers);
+        }
+    };
+    public static final Type<AttributeModifiers1_21> TYPE1_21_6 = new Type<>(AttributeModifiers1_21.class) {
+        @Override
+        public AttributeModifiers1_21 read(final ByteBuf buffer) {
+            final AttributeModifier[] modifiers = AttributeModifier.ARRAY_TYPE1_21_6.read(buffer);
+            return new AttributeModifiers1_21(modifiers);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final AttributeModifiers1_21 value) {
+            AttributeModifier.ARRAY_TYPE1_21_6.write(buffer, value.modifiers());
+        }
+
+        @Override
+        public void write(final Ops ops, final AttributeModifiers1_21 value) {
+            ops.write(AttributeModifier.ARRAY_TYPE1_21_6, value.modifiers);
+        }
+    };
 
     public AttributeModifiers1_21 rewrite(final Int2IntFunction rewriteFunction) {
         final AttributeModifier[] modifiers = new AttributeModifier[this.modifiers.length];
         for (int i = 0; i < this.modifiers.length; i++) {
             final AttributeModifier modifier = this.modifiers[i];
-            modifiers[i] = new AttributeModifier(rewriteFunction.applyAsInt(modifier.attribute()), modifier.modifier(), modifier.slotType());
+            modifiers[i] = new AttributeModifier(rewriteFunction.applyAsInt(modifier.attribute()), modifier.modifier(), modifier.slotType(), modifier.display());
         }
         return new AttributeModifiers1_21(modifiers, showInTooltip);
     }
 
-    public record AttributeModifier(int attribute, ModifierData modifier, int slotType) {
+    @Override
+    public AttributeModifiers1_21 copy() {
+        return new AttributeModifiers1_21(Copyable.copy(modifiers), showInTooltip);
+    }
 
-        public static final Type<AttributeModifier> TYPE = new Type<>(AttributeModifier.class) {
+    @Override
+    public AttributeModifiers1_21 rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
+        final FullMappings mappings = protocol.getMappingData().getAttributeMappings();
+        if (mappings == null) {
+            return this;
+        }
+
+        final List<AttributeModifier> modifiers = new ArrayList<>(this.modifiers.length);
+        for (final AttributeModifier modifier : this.modifiers) {
+            final int mappedId = clientbound ? mappings.getNewId(modifier.attribute()) : mappings.inverse().getNewId(modifier.attribute());
+            if (mappedId != -1) {
+                modifiers.add(new AttributeModifier(mappedId, modifier.modifier(), modifier.slotType(), modifier.display()));
+            }
+        }
+        return new AttributeModifiers1_21(modifiers.toArray(AttributeModifier[]::new), this.showInTooltip);
+    }
+
+    public record AttributeModifier(int attribute, ModifierData modifier, int slotType, Display display) {
+        private static final String[] EQUIPMENT_SLOT_GROUPS = {"any", "mainhand", "offhand", "hand", "feet", "legs", "chest", "head", "armor", "body", "saddle"};
+        private static final String[] OPERATION = {"add_value", "add_multiplied_base", "add_multiplied_total"};
+
+        public AttributeModifier(final int attribute, final ModifierData modifier, final int slotType) {
+            this(attribute, modifier, slotType, Display.DEFAULT);
+        }
+
+        public static final Type<AttributeModifier> TYPE1_21 = new Type<>(AttributeModifier.class) {
             @Override
             public AttributeModifier read(final ByteBuf buffer) {
                 final int attribute = Types.VAR_INT.readPrimitive(buffer);
@@ -71,8 +147,62 @@ public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean show
                 ModifierData.TYPE.write(buffer, value.modifier);
                 Types.VAR_INT.writePrimitive(buffer, value.slotType);
             }
+
+            @Override
+            public void write(final Ops ops, final AttributeModifier value) {
+                final Key attribute = ops.context().registryAccess().attributeModifier(value.attribute);
+                ops.writeMap(map -> map
+                    .write("type", Types.RESOURCE_LOCATION, attribute)
+                    .write("id", Types.RESOURCE_LOCATION, Key.of(value.modifier.id()))
+                    .write("amount", Types.DOUBLE, value.modifier.amount)
+                    .write("operation", Types.STRING, OPERATION[value.modifier.operation()])
+                    .writeOptional("slot", Types.STRING, EQUIPMENT_SLOT_GROUPS[value.slotType()], "any"));
+            }
         };
-        public static final Type<AttributeModifier[]> ARRAY_TYPE = new ArrayType<>(TYPE);
+        public static final Type<AttributeModifier[]> ARRAY_TYPE1_21 = new ArrayType<>(TYPE1_21);
+
+        public static final Type<AttributeModifier> TYPE1_21_6 = new Type<>(AttributeModifier.class) {
+            @Override
+            public AttributeModifier read(final ByteBuf buffer) {
+                final int attribute = Types.VAR_INT.readPrimitive(buffer);
+                final ModifierData modifier = ModifierData.TYPE.read(buffer);
+                final int slot = Types.VAR_INT.readPrimitive(buffer);
+                final int displayType = Types.VAR_INT.readPrimitive(buffer);
+                final Display display = displayType == OverrideText.ID ? new OverrideText(Types.TAG.read(buffer)) : new Display(displayType);
+                return new AttributeModifier(attribute, modifier, slot, display);
+            }
+
+            @Override
+            public void write(final ByteBuf buffer, final AttributeModifier value) {
+                Types.VAR_INT.writePrimitive(buffer, value.attribute);
+                ModifierData.TYPE.write(buffer, value.modifier);
+                Types.VAR_INT.writePrimitive(buffer, value.slotType);
+                value.display.write(buffer);
+            }
+
+            @Override
+            public void write(final Ops ops, final AttributeModifier value) {
+                final Key attribute = ops.context().registryAccess().attributeModifier(value.attribute);
+                ops.writeMap(map -> {
+                    map.write("type", Types.RESOURCE_LOCATION, attribute)
+                        .write("id", Types.RESOURCE_LOCATION, Key.of(value.modifier.id()))
+                        .write("amount", Types.DOUBLE, value.modifier.amount)
+                        .write("operation", Types.STRING, OPERATION[value.modifier.operation()])
+                        .writeOptional("slot", Types.STRING, EQUIPMENT_SLOT_GROUPS[value.slotType()], "any");
+                    if (value.display.equals(Display.DEFAULT)) {
+                        return;
+                    }
+
+                    map.writeMap("display", display -> {
+                        display.write("type", Types.STRING, Display.DISPLAY_TYPES[value.display.id()]);
+                        if (value.display instanceof final OverrideText overrideText) {
+                            display.write("value", Types.TEXT_COMPONENT_TAG, overrideText.component);
+                        }
+                    });
+                });
+            }
+        };
+        public static final Type<AttributeModifier[]> ARRAY_TYPE1_21_6 = new ArrayType<>(TYPE1_21_6);
     }
 
     public record ModifierData(String id, double amount, int operation) {
@@ -94,4 +224,52 @@ public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean show
             }
         };
     }
+
+    public static class Display implements Copyable {
+        public static final String[] DISPLAY_TYPES = {"default", "hidden", "override_text"};
+        public static final Display DEFAULT = new Display(0);
+        private final int id;
+
+        public Display(final int id) {
+            this.id = id;
+        }
+
+        public int id() {
+            return this.id;
+        }
+
+        public void write(final ByteBuf buf) {
+            Types.VAR_INT.writePrimitive(buf, this.id);
+        }
+
+        @Override
+        public Display copy() {
+            return this;
+        }
+    }
+
+    public static final class OverrideText extends Display {
+        public static final int ID = 2;
+        private final Tag component;
+
+        public OverrideText(final Tag component) {
+            super(ID);
+            this.component = component;
+        }
+
+        public Tag component() {
+            return this.component;
+        }
+
+        @Override
+        public void write(final ByteBuf buf) {
+            super.write(buf);
+            Types.TAG.write(buf, this.component);
+        }
+
+        @Override
+        public OverrideText copy() {
+            return new OverrideText(this.component.copy());
+        }
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/Bee.java

@@ -23,29 +23,73 @@
 package com.viaversion.viaversion.api.minecraft.item.data;
 
 import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.viaversion.api.minecraft.codec.Ops;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.util.Copyable;
 import io.netty.buffer.ByteBuf;
 
-public record Bee(CompoundTag entityData, int ticksInHive, int minTicksInHive) {
+public record Bee(EntityData entityData, int ticksInHive, int minTicksInHive) implements Copyable {
 
-    public static final Type<Bee> TYPE = new Type<>(Bee.class) {
+    public Bee(final CompoundTag entityData, final int ticksInHive, final int minTicksInHive) {
+        this(new EntityData(-1, entityData), ticksInHive, minTicksInHive);
+    }
+
+    public static final Type<Bee> TYPE1_20_5 = new Type<>(Bee.class) {
         @Override
         public Bee read(final ByteBuf buffer) {
             final CompoundTag entityData = Types.COMPOUND_TAG.read(buffer);
             final int ticksInHive = Types.VAR_INT.readPrimitive(buffer);
             final int minTicksInHive = Types.VAR_INT.readPrimitive(buffer);
+            return new Bee(new EntityData(-1, entityData), ticksInHive, minTicksInHive);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final Bee value) {
+            Types.COMPOUND_TAG.write(buffer, value.entityData.tag());
+            Types.VAR_INT.writePrimitive(buffer, value.ticksInHive);
+            Types.VAR_INT.writePrimitive(buffer, value.minTicksInHive);
+        }
+
+        @Override
+        public void write(final Ops ops, final Bee value) {
+            ops.writeMap(map -> map
+                .writeOptional("entity_data", Types.COMPOUND_TAG, value.entityData.tag(), new CompoundTag())
+                .write("ticks_in_hive", Types.INT, value.ticksInHive)
+                .write("min_ticks_in_hive", Types.INT, value.minTicksInHive));
+        }
+    };
+    public static final Type<Bee[]> ARRAY_TYPE1_20_5 = new ArrayType<>(TYPE1_20_5);
+
+    public static final Type<Bee> TYPE1_21_9 = new Type<>(Bee.class) {
+        @Override
+        public Bee read(final ByteBuf buffer) {
+            final EntityData entityData = EntityData.TYPE.read(buffer);
+            final int ticksInHive = Types.VAR_INT.readPrimitive(buffer);
+            final int minTicksInHive = Types.VAR_INT.readPrimitive(buffer);
             return new Bee(entityData, ticksInHive, minTicksInHive);
         }
 
         @Override
         public void write(final ByteBuf buffer, final Bee value) {
-            Types.COMPOUND_TAG.write(buffer, value.entityData);
+            EntityData.TYPE.write(buffer, value.entityData);
             Types.VAR_INT.writePrimitive(buffer, value.ticksInHive);
             Types.VAR_INT.writePrimitive(buffer, value.minTicksInHive);
         }
-    };
-    public static final Type<Bee[]> ARRAY_TYPE = new ArrayType<>(TYPE);
 
+        @Override
+        public void write(final Ops ops, final Bee value) {
+            ops.writeMap(map -> map
+                .write("entity_data", EntityData.TYPE, value.entityData)
+                .write("ticks_in_hive", Types.INT, value.ticksInHive)
+                .write("min_ticks_in_hive", Types.INT, value.minTicksInHive));
+        }
+    };
+    public static final Type<Bee[]> ARRAY_TYPE1_21_9 = new ArrayType<>(TYPE1_21_9);
+
+    @Override
+    public Bee copy() {
+        return new Bee(entityData.copy(), ticksInHive, minTicksInHive);
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/BlockEntityData.java

@@ -0,0 +1,65 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2025 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.minecraft.item.data;
+
+import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.codec.Ops;
+import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.util.Rewritable;
+import io.netty.buffer.ByteBuf;
+
+public record BlockEntityData(int type, CompoundTag tag) implements Rewritable {
+
+    public static final Type<BlockEntityData> TYPE = new Type<>(BlockEntityData.class) {
+        @Override
+        public BlockEntityData read(final ByteBuf buffer) {
+            final int type = Types.VAR_INT.readPrimitive(buffer);
+            final CompoundTag tag = Types.COMPOUND_TAG.read(buffer);
+            return new BlockEntityData(type, tag);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final BlockEntityData value) {
+            Types.VAR_INT.writePrimitive(buffer, value.type);
+            Types.COMPOUND_TAG.write(buffer, value.tag);
+        }
+
+        @Override
+        public void write(final Ops ops, final BlockEntityData data) {
+            ops.writeMap(map -> map
+                .write("id", Types.RESOURCE_LOCATION, ops.context().registryAccess().blockEntity(data.type))
+                .writeInlinedMap(Types.COMPOUND_TAG, data.tag)
+            );
+        }
+    };
+
+    @Override
+    public BlockEntityData rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
+        final int mappedType = protocol.getMappingData().getBlockEntityMappings().getNewId(type);
+        // Empty mappings might be possible for removed block entities, set a dummy value in that case. Will be handled fine by server and client without losing data
+        return new BlockEntityData(mappedType != -1 ? mappedType : 0, tag);
+    }
+}