Fix 1.21 player chat read type

Replaced by Protocol#registerClientbound & Protocol#registerServerbound

.github/FUNDING.yml

@@ -1,3 +1,3 @@
 github: kennytv
 patreon: kennytv
-custom: ['https://florianmichael.de/donate']
+custom: ['https://florianreuth.de/donate']

.github/dependabot.yml

@@ -6,3 +6,9 @@ updates:
     directory: "/"
     schedule:
       interval: "monthly"
+  - package-ecosystem: "gradle"
+    cooldown:
+      default-days: 7
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/build.yml

@@ -11,13 +11,13 @@ jobs:
     timeout-minutes: 30
     steps:
     - name: Checkout Repository
-      uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # 6.0.1
+      uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # 6.0.2
       with:
         persist-credentials: false
     - name: Set up Gradle
-      uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # 5.0.0
+      uses: gradle/actions/setup-gradle@f29f5a9d7b09a7c6b29859002d29d24e1674c884 # 5.0.1
     - name: Set up JDK 17
-      uses: actions/setup-java@f2beeb24e141e01a676f977032f5a29d81c9e27e # 5.1.0
+      uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # 5.2.0
       with:
         distribution: 'temurin'
         java-version: 17

.github/workflows/publish.yml

@@ -16,13 +16,13 @@ jobs:
     timeout-minutes: 30
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # 6.0.1
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # 6.0.2
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # 5.0.0
+        uses: gradle/actions/setup-gradle@f29f5a9d7b09a7c6b29859002d29d24e1674c884 # 5.0.1
       - name: Set up JDK 17
-        uses: actions/setup-java@f2beeb24e141e01a676f977032f5a29d81c9e27e # 5.1.0
+        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # 5.2.0
         with:
           distribution: 'temurin'
           java-version: 17

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

@@ -1,22 +0,0 @@
-name: Update Gradle Wrapper
-on:
-  workflow_dispatch:
-  schedule:
-    - cron: "0 0 * * 0"
-
-permissions:
-  contents: write
-  pull-requests: write
-
-jobs:
-  update-gradle-wrapper:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 30
-    steps:
-      - name: Checkout Repository
-        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # 6.0.1
-        with:
-          fetch-depth: 0
-          persist-credentials: false
-      - name: Update Gradle Wrapper
-        uses: gradle-update/update-gradle-wrapper-action@512b1875f3b6270828abfe77b247d5895a2da1e5 # 2.1.0

README.md

@@ -7,11 +7,15 @@
 **Allows the connection of higher client versions to lower server versions -
 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, 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.**
+The base ViaVersion jar runs on [Paper](https://papermc.io/software/paper/)
+and [Velocity](https://papermc.io/software/velocity/). We also have projects integrating ViaVersion to run
+on [Fabric](https://github.com/ViaVersion/ViaFabric), [Forge](https://github.com/ViaVersion/ViaForge), [Bungee](https://github.com/ViaVersion/ViaBungee), [Sponge](https://github.com/ViaVersion/ViaSponge),
+or as [a standalone proxy](https://github.com/ViaVersion/ViaProxy) 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
+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
 direct access to client/server state and more extensive API.
 
 Supported Versions:
@@ -22,10 +26,16 @@ Supported Versions:
 
 Snapshot support
 --------
-**ViaVersion will only be released a few days *after* a Minecraft update** unless the protocol changes of the update were trivial. If you want early-access, usually days or even weeks before the final release, you can subscribe to either:
-- [GitHub Sponsors](https://github.com/sponsors/kennytv/sponsorships?sponsor=kennytv&tier_id=385613&preview=false) (preferred option. Use the `/verify` command on this Discord after), or alternatively
-- [Patreon](https://www.patreon.com/kennytv/membership) (see the highest tier and make sure to link Patreon to your Discord account under Settings->Connections)
-  This also includes access to a private repository with the code, which will be pushed to the public repository after the given delay on a Minecraft update.
+**ViaVersion will only be released a few days *after* a Minecraft update** unless the protocol changes of the update
+were trivial. If you want early-access, usually days or even weeks before the final release, you can subscribe to
+either:
+
+- [GitHub Sponsors](https://github.com/sponsors/kennytv/sponsorships?sponsor=kennytv&tier_id=385613&preview=false) (
+  preferred option. Use the `/verify` command on this Discord after), or alternatively
+- [Patreon](https://www.patreon.com/kennytv/membership) (see the highest tier and make sure to link Patreon to your
+  Discord account under Settings->Connections)
+  This also includes access to a private repository with the code, which will be pushed to the public repository after
+  the given delay on a Minecraft update.
 
 Releases/Dev Builds
 --------
@@ -89,7 +99,8 @@ 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).
+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
 --------

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) 2016-2025 ViaVersion and contributors
+ * Copyright (C) 2016-2026 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/connection/ProtocolInfo.java

@@ -134,6 +134,15 @@ public interface ProtocolInfo {
 
     void setUuid(UUID uuid);
 
+    /**
+     * Returns whether compression is enabled for this connection.
+     *
+     * @return whether compression is enabled
+     */
+    boolean compressionEnabled();
+
+    void setCompressionEnabled(boolean compressionEnabled);
+
     /**
      * Returns the user's pipeline.
      *

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

@@ -0,0 +1,123 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.data.MappingDataLoader.IdentifiersPair;
+import com.viaversion.viaversion.util.Key;
+import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class FullIdentityMappings implements FullMappings {
+    private static final String[] EMPTY_ARRAY = new String[0];
+    private final Object2IntMap<String> stringToId;
+    private final String[] idToString;
+    private final Mappings mappings;
+
+    public FullIdentityMappings(final IdentifiersPair identifiersPair, final Mappings mappings) {
+        Preconditions.checkNotNull(mappings, "Mappings cannot be null");
+        this.mappings = mappings;
+        this.stringToId = FullMappingsBase.toInverseMap(identifiersPair.unmapped());
+        this.idToString = identifiersPair.unmapped().toArray(EMPTY_ARRAY);
+    }
+
+    private FullIdentityMappings(final Object2IntMap<String> stringToId, final String[] idToString, final Mappings mappings) {
+        this.stringToId = stringToId;
+        this.idToString = idToString;
+        this.mappings = mappings;
+    }
+
+    @Override
+    public int id(final String identifier) {
+        return stringToId.getInt(Key.stripMinecraftNamespace(identifier));
+    }
+
+    @Override
+    public int mappedId(final String mappedIdentifier) {
+        return id(mappedIdentifier);
+    }
+
+    @Override
+    public String identifier(final int id) {
+        if (id < 0 || id >= idToString.length) {
+            return null;
+        }
+        final String identifier = idToString[id];
+        return Key.namespaced(identifier);
+    }
+
+    @Override
+    public @Nullable String identifier(final String mappedIdentifier) {
+        final int mappedId = mappedId(mappedIdentifier);
+        if (mappedId == -1) {
+            return null;
+        }
+        final int id = mappings.inverse().getNewId(mappedId);
+        return id != -1 ? identifier(id) : null;
+    }
+
+    @Override
+    public @Nullable String mappedIdentifier(final int mappedId) {
+        return identifier(mappedId);
+    }
+
+    @Override
+    public @Nullable String mappedIdentifier(final String identifier) {
+        return identifier(identifier);
+    }
+
+    @Override
+    public int getNewId(int id) {
+        return mappings.getNewId(id);
+    }
+
+    @Override
+    public void setNewId(int id, int mappedId) {
+        mappings.setNewId(id, mappedId);
+    }
+
+    @Override
+    public int size() {
+        return mappings.size();
+    }
+
+    @Override
+    public int mappedSize() {
+        return mappings.mappedSize();
+    }
+
+    @Override
+    public boolean isIdentity() {
+        return true;
+    }
+
+    @Override
+    public boolean isIntIdIdentity() {
+        return true;
+    }
+
+    @Override
+    public FullMappings inverse() {
+        return new FullIdentityMappings(stringToId, idToString, mappings.inverse());
+    }
+}

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

@@ -77,6 +77,14 @@ public interface FullMappings extends BiMappings {
      */
     @Nullable String mappedIdentifier(String identifier);
 
+    /**
+     * Returns whether the int id mappings are identity mappings.
+     *
+     * @return whether the int id mappings are identity mappings
+     * @see #isIdentity()
+     */
+    boolean isIntIdIdentity();
+
     @Override
     FullMappings inverse();
 }

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

@@ -23,6 +23,7 @@
 package com.viaversion.viaversion.api.data;
 
 import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.data.MappingDataLoader.IdentifiersPair;
 import com.viaversion.viaversion.util.Key;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
 import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
@@ -37,13 +38,13 @@ public class FullMappingsBase implements FullMappings {
     private final String[] mappedIdToString;
     private final Mappings mappings;
 
-    public FullMappingsBase(final List<String> unmappedIdentifiers, final List<String> mappedIdentifiers, final Mappings mappings) {
+    public FullMappingsBase(final IdentifiersPair identifiersPair, final Mappings mappings) {
         Preconditions.checkNotNull(mappings, "Mappings cannot be null");
         this.mappings = mappings;
-        this.stringToId = toInverseMap(unmappedIdentifiers);
-        this.mappedStringToId = toInverseMap(mappedIdentifiers);
-        this.idToString = unmappedIdentifiers.toArray(EMPTY_ARRAY);
-        this.mappedIdToString = mappedIdentifiers.toArray(EMPTY_ARRAY);
+        this.stringToId = toInverseMap(identifiersPair.unmapped());
+        this.idToString = identifiersPair.unmapped().toArray(EMPTY_ARRAY);
+        this.mappedStringToId = toInverseMap(identifiersPair.mapped());
+        this.mappedIdToString = identifiersPair.mapped().toArray(EMPTY_ARRAY);
     }
 
     private FullMappingsBase(final Object2IntMap<String> stringToId, final Object2IntMap<String> mappedStringToId, final String[] idToString, final String[] mappedIdToString, final Mappings mappings) {
@@ -54,7 +55,11 @@ public class FullMappingsBase implements FullMappings {
         this.mappings = mappings;
     }
 
-    private static Object2IntMap<String> toInverseMap(final List<String> list) {
+    public static FullMappings of(final IdentifiersPair identifiersPair, final Mappings mappings) {
+        return mappings.isIdentity() && identifiersPair.identity() ? new FullIdentityMappings(identifiersPair, mappings) : new FullMappingsBase(identifiersPair, mappings);
+    }
+
+    static Object2IntMap<String> toInverseMap(final List<String> list) {
         final Object2IntMap<String> map = new Object2IntOpenHashMap<>(list.size());
         map.defaultReturnValue(-1);
         for (int i = 0; i < list.size(); i++) {
@@ -135,6 +140,11 @@ public class FullMappingsBase implements FullMappings {
         return mappings.mappedSize();
     }
 
+    @Override
+    public boolean isIntIdIdentity() {
+        return mappings.isIdentity();
+    }
+
     @Override
     public FullMappings inverse() {
         return new FullMappingsBase(mappedStringToId, stringToId, mappedIdToString, idToString, mappings.inverse());

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

@@ -38,4 +38,9 @@ public record IdentityMappings(int size, int mappedSize) implements Mappings {
     public Mappings inverse() {
         return new IdentityMappings(mappedSize, size);
     }
+
+    @Override
+    public boolean isIdentity() {
+        return true;
+    }
 }

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

@@ -170,6 +170,8 @@ public interface MappingData {
 
     @Nullable FullMappings getRecipeSerializerMappings();
 
+    @Nullable FullMappings getSlotDisplayMappings();
+
     @Nullable FullMappings getDataComponentSerializerMappings();
 
     default @Nullable FullMappings getFullMappings(final MappingType mappingType) {

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

@@ -26,6 +26,7 @@ import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.IntArrayTag;
 import com.viaversion.nbt.tag.Tag;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.data.MappingDataLoader.IdentifiersPair;
 import com.viaversion.viaversion.api.minecraft.RegistryType;
 import com.viaversion.viaversion.api.minecraft.TagData;
 import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
@@ -45,6 +46,7 @@ public class MappingDataBase implements MappingData {
     protected FullMappings entityMappings;
     protected FullMappings recipeSerializerMappings;
     protected FullMappings itemDataSerializerMappings;
+    protected FullMappings slotDisplayMappings;
     protected FullMappings attributeMappings;
     protected FullMappings blockEntityMappings;
     protected ParticleMappings particleMappings;
@@ -89,19 +91,19 @@ public class MappingDataBase implements MappingData {
 
             entityMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "entities");
             argumentTypeMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "argumenttypes");
+            slotDisplayMappings = loadFullMappings(data, unmappedIdentifierData, mappedIdentifierData, "slot_displays");
             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");
-            if (unmappedParticles != null && mappedParticles != null) {
+            final IdentifiersPair particleIdentifiers = identifiersFromGlobalIds(unmappedIdentifierData, mappedIdentifierData, "particles");
+            if (particleIdentifiers != null) {
                 Mappings particleMappings = loadMappings(data, "particles");
                 if (particleMappings == null) {
-                    particleMappings = new IdentityMappings(unmappedParticles.size(), mappedParticles.size());
+                    particleMappings = new IdentityMappings(particleIdentifiers.unmapped().size(), particleIdentifiers.mapped().size());
                 }
-                this.particleMappings = new ParticleMappings(unmappedParticles, mappedParticles, particleMappings);
+                this.particleMappings = new ParticleMappings(particleIdentifiers, particleMappings);
             }
         } else {
             // Might not have identifiers in older versions
@@ -130,6 +132,10 @@ public class MappingDataBase implements MappingData {
         return MappingDataLoader.INSTANCE.identifiersFromGlobalIds(mappingsTag, key);
     }
 
+    protected @Nullable IdentifiersPair identifiersFromGlobalIds(final CompoundTag unmappedTag, final CompoundTag mappedTag, final String key) {
+        return MappingDataLoader.INSTANCE.identifiersFromGlobalIds(unmappedTag, mappedTag, key);
+    }
+
     protected @Nullable CompoundTag readMappingsFile(final String name) {
         return MappingDataLoader.INSTANCE.loadNBT(name);
     }
@@ -156,14 +162,12 @@ public class MappingDataBase implements MappingData {
             return null;
         }
 
-        final List<String> unmappedIdentifiers = identifiersFromGlobalIds(unmappedIdentifiersTag, key);
-        final List<String> mappedIdentifiers = identifiersFromGlobalIds(mappedIdentifiersTag, key);
+        final IdentifiersPair identifiersPair = identifiersFromGlobalIds(unmappedIdentifiersTag, mappedIdentifiersTag, key);
         Mappings mappings = loadBiMappings(data, key); // Load as bi-mappings to keep the inverse cached
         if (mappings == null) {
-            mappings = new IdentityMappings(unmappedIdentifiers.size(), mappedIdentifiers.size());
+            mappings = new IdentityMappings(identifiersPair.unmapped().size(), identifiersPair.mapped().size());
         }
-
-        return new FullMappingsBase(unmappedIdentifiers, mappedIdentifiers, mappings);
+        return FullMappingsBase.of(identifiersPair, mappings);
     }
 
     protected @Nullable BiMappings loadBiMappings(final CompoundTag data, final String key) {
@@ -335,6 +339,11 @@ public class MappingDataBase implements MappingData {
         return recipeSerializerMappings;
     }
 
+    @Override
+    public @Nullable FullMappings getSlotDisplayMappings() {
+        return slotDisplayMappings;
+    }
+
     @Override
     public @Nullable IntSet changedBlocks() {
         return changedBlocks;

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

@@ -81,8 +81,9 @@ public class MappingDataLoader {
         for (final Map.Entry<String, Tag> entry : globalIdentifiers.entrySet()) {
             //noinspection unchecked
             final ListTag<StringTag> value = (ListTag<StringTag>) entry.getValue();
-            final String[] array = new String[value.size()];
-            for (int i = 0, size = value.size(); i < size; i++) {
+            final int size = value.size();
+            final String[] array = new String[size];
+            for (int i = 0; i < size; i++) {
                 array[i] = value.get(i).getValue();
             }
             GLOBAL_IDENTIFIER_INDEXES.put(entry.getKey(), array);
@@ -272,13 +273,60 @@ public class MappingDataLoader {
 
     public @Nullable List<String> identifiersFromGlobalIds(final CompoundTag mappingsTag, final String key) {
         final Mappings mappings = loadMappings(mappingsTag, key);
-        if (mappings == null) {
+        return mappings != null ? identifiers(mappings, key) : null;
+
+    }
+
+    /**
+     * Returns a pair of identifier lists, also keeping track of whether the two lists are equal.
+     *
+     * @param unmappedTag unmapped mappings tag
+     * @param mappedTag   mapped mappings tag
+     * @param key         mappings key
+     * @return pair of identifier lists
+     */
+    public @Nullable IdentifiersPair identifiersFromGlobalIds(final CompoundTag unmappedTag, final CompoundTag mappedTag, final String key) {
+        final Mappings unmapped = loadMappings(unmappedTag, key);
+        if (unmapped == null) {
             return null;
         }
 
+        final Mappings mapped = loadMappings(mappedTag, key);
+        if (mapped == null) {
+            return null;
+        }
+
+        final int size = unmapped.size();
+        if (size != mapped.size()) {
+            return new IdentifiersPair(identifiers(unmapped, key), identifiers(mapped, key), false);
+        }
+
+        // Small optimization to only load one array and reduce loading for full mappings
+        final List<String> unmappedIdentifiers = new ArrayList<>(size);
+        final List<String> mappedIdentifiers = new ArrayList<>(size);
+        boolean identity = true;
+        for (int i = 0; i < size; i++) {
+            final int unmappedGlobalId = unmapped.getNewId(i);
+            final int mappedGlobalId = mapped.getNewId(i);
+            final String unmappedIdentifier = identifierFromGlobalId(key, unmappedGlobalId);
+            if (unmappedGlobalId == mappedGlobalId) {
+                unmappedIdentifiers.add(unmappedIdentifier);
+                mappedIdentifiers.add(unmappedIdentifier);
+                continue;
+            }
+
+            identity = false;
+            unmappedIdentifiers.add(unmappedIdentifier);
+            mappedIdentifiers.add(identifierFromGlobalId(key, mappedGlobalId));
+        }
+        return identity ? new IdentifiersPair(unmappedIdentifiers) : new IdentifiersPair(unmappedIdentifiers, mappedIdentifiers);
+    }
+
+    private List<String> identifiers(final Mappings mappings, final String key) {
         final List<String> identifiers = new ArrayList<>(mappings.size());
         for (int i = 0; i < mappings.size(); i++) {
-            identifiers.add(identifierFromGlobalId(key, mappings.getNewId(i)));
+            final int globalId = mappings.getNewId(i);
+            identifiers.add(identifierFromGlobalId(key, globalId));
         }
         return identifiers;
     }
@@ -342,4 +390,15 @@ public class MappingDataLoader {
 
         T create(V mappings, int mappedSize);
     }
+
+    public record IdentifiersPair(List<String> unmapped, List<String> mapped, boolean identity) {
+
+        public IdentifiersPair(final List<String> unmapped, final List<String> mapped) {
+            this(unmapped, mapped, false);
+        }
+
+        public IdentifiersPair(final List<String> identifiers) {
+            this(identifiers, identifiers, true);
+        }
+    }
 }

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

@@ -22,6 +22,8 @@
  */
 package com.viaversion.viaversion.api.data;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 public interface Mappings {
 
     /**
@@ -84,4 +86,40 @@ public interface Mappings {
      * @return mappings with keys and values swapped
      */
     Mappings inverse();
+
+
+    /**
+     * Returns whether the mappings are unchanged identity mappings.
+     *
+     * @return whether the mappings are unchanged identity mappings
+     */
+    default boolean isIdentity() {
+        return false;
+    }
+
+    /**
+     * Returns whether the mappings null or identity mappings.
+     *
+     * @param mappings mappings
+     * @return whether the mappings are identity mappings
+     * @see #isFullIdentity(Mappings)
+     */
+    static boolean isIntIdIdentity(@Nullable final Mappings mappings) {
+        if (mappings == null) {
+            return true;
+        }
+        return mappings instanceof FullMappings fullMappings ? fullMappings.isIntIdIdentity() : mappings.isIdentity();
+    }
+
+    /**
+     * Returns whether the mappings null or full identity mappings.
+     * Stronger than {@link #isIntIdIdentity(Mappings)}, but equal to that if not {@link FullMappings}.
+     *
+     * @param mappings mappings
+     * @return whether the mappings are full identity mappings
+     * @see #isIntIdIdentity(Mappings)
+     */
+    static boolean isFullIdentity(@Nullable final Mappings mappings) {
+        return mappings == null || mappings.isIdentity();
+    }
 }

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

@@ -22,16 +22,16 @@
  */
 package com.viaversion.viaversion.api.data;
 
+import com.viaversion.viaversion.api.data.MappingDataLoader.IdentifiersPair;
 import it.unimi.dsi.fastutil.ints.IntArrayList;
 import it.unimi.dsi.fastutil.ints.IntList;
-import java.util.List;
 
 public class ParticleMappings extends FullMappingsBase {
     private final IntList itemParticleIds = new IntArrayList(4);
     private final IntList blockParticleIds = new IntArrayList(4);
 
-    public ParticleMappings(final List<String> unmappedIdentifiers, final List<String> mappedIdentifiers, final Mappings mappings) {
-        super(unmappedIdentifiers, mappedIdentifiers, mappings);
+    public ParticleMappings(final IdentifiersPair identifiersPair, final Mappings mappings) {
+        super(identifiersPair, mappings);
         addBlockParticle("block");
         addBlockParticle("falling_dust");
         addBlockParticle("block_marker");

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

@@ -22,6 +22,7 @@
  */
 package com.viaversion.viaversion.api.minecraft;
 
+import com.google.common.base.Preconditions;
 import com.viaversion.nbt.tag.ListTag;
 import com.viaversion.nbt.tag.StringTag;
 import com.viaversion.nbt.tag.Tag;
@@ -40,6 +41,7 @@ public interface HolderSet {
      * @return a new holder set
      */
     static HolderSet of(final String tagKey) {
+        Preconditions.checkNotNull(tagKey);
         return new HolderSetImpl.Tag(tagKey);
     }
 
@@ -50,6 +52,7 @@ public interface HolderSet {
      * @return a new holder set
      */
     static HolderSet of(final int[] ids) {
+        Preconditions.checkNotNull(ids);
         return new HolderSetImpl.Ids(ids);
     }
 

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

@@ -58,8 +58,8 @@ public record PaintingVariant(int width, int height, String assetId, @Nullable T
             final int width = Types.VAR_INT.readPrimitive(buffer);
             final int height = Types.VAR_INT.readPrimitive(buffer);
             final String assetId = Types.STRING.read(buffer);
-            final Tag title = Types.OPTIONAL_TAG.read(buffer);
-            final Tag author = Types.OPTIONAL_TAG.read(buffer);
+            final Tag title = Types.TRUSTED_OPTIONAL_TAG.read(buffer);
+            final Tag author = Types.TRUSTED_OPTIONAL_TAG.read(buffer);
             return new PaintingVariant(width, height, assetId, title, author);
         }
 
@@ -68,8 +68,8 @@ public record PaintingVariant(int width, int height, String assetId, @Nullable T
             Types.VAR_INT.writePrimitive(buffer, variant.width());
             Types.VAR_INT.writePrimitive(buffer, variant.height());
             Types.STRING.write(buffer, variant.assetId());
-            Types.OPTIONAL_TAG.write(buffer, variant.title());
-            Types.OPTIONAL_TAG.write(buffer, variant.author());
+            Types.TRUSTED_OPTIONAL_TAG.write(buffer, variant.title());
+            Types.TRUSTED_OPTIONAL_TAG.write(buffer, variant.author());
         }
 
         @Override
@@ -79,8 +79,8 @@ public record PaintingVariant(int width, int height, String assetId, @Nullable T
                 .write("width", Types.INT, value.width())
                 .write("height", Types.INT, value.height())
                 .write("asset_id", Types.IDENTIFIER, Key.of(value.assetId()))
-                .writeOptional("title", Types.TAG, value.title())
-                .writeOptional("author", Types.TAG, value.author()));
+                .writeOptional("title", Types.TRUSTED_TAG, value.title())
+                .writeOptional("author", Types.TRUSTED_TAG, value.author()));
         }
 
         @Override

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

@@ -34,7 +34,9 @@ public enum RegistryType implements RegistryKey {
     FLUID("fluid"),
     ENTITY("entity_type"),
     GAME_EVENT("game_event"),
-    ENCHANTMENT("enchantment");
+    ENCHANTMENT("enchantment"),
+    DAMAGE_TYPE("damage_type"),
+    BANNER_PATTERN("banner_pattern");
 
     private static final Map<String, RegistryType> MAP = new HashMap<>();
     private static final RegistryType[] VALUES = values();

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

@@ -61,6 +61,17 @@ public interface ChunkSection {
 
     void setNonAirBlocksCount(int nonAirBlocksCount);
 
+    /**
+     * Returns the number of fluid blocks in this section.
+     * <p>
+     * Available with versions 26.1+.
+     *
+     * @return fluid blocks in this section
+     */
+    int getFluidCount();
+
+    void setFluidCount(int fluidCount);
+
     /**
      * Returns whether this section holds light data.
      * Only true for &lt; 1.14 chunks.

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

@@ -30,6 +30,7 @@ public class ChunkSectionImpl implements ChunkSection {
     private final EnumMap<PaletteType, DataPalette> palettes = new EnumMap<>(PaletteType.class);
     private ChunkSectionLight light;
     private int nonAirBlocksCount;
+    private int fluidCount;
 
     public ChunkSectionImpl() {
     }
@@ -58,6 +59,16 @@ public class ChunkSectionImpl implements ChunkSection {
         this.nonAirBlocksCount = nonAirBlocksCount;
     }
 
+    @Override
+    public int getFluidCount() {
+        return fluidCount;
+    }
+
+    @Override
+    public void setFluidCount(final int fluidCount) {
+        this.fluidCount = fluidCount;
+    }
+
     @Override
     public @Nullable ChunkSectionLight getLight() {
         return light;

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

@@ -160,6 +160,10 @@ public final class StructuredDataContainer implements Copyable {
     }
 
     public <T, V> void replace(final StructuredDataKey<T> key, final StructuredDataKey<V> toKey, final Function<T, @Nullable V> valueMapper) {
+        replace(key, toKey, valueMapper, null);
+    }
+
+    public <T, V> void replace(final StructuredDataKey<T> key, final StructuredDataKey<V> toKey, final Function<T, @Nullable V> valueMapper, final Runnable emptyValueHandler) {
         final StructuredData<?> data = this.data.remove(key);
         if (data == null) {
             return;
@@ -175,6 +179,9 @@ public final class StructuredDataContainer implements Copyable {
         } else {
             // Also replace the key for empty data
             setEmpty(toKey);
+            if (emptyValueHandler != null) {
+                emptyValueHandler.run();
+            }
         }
     }
 

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

@@ -37,6 +37,7 @@ import com.viaversion.viaversion.api.minecraft.data.version.StructuredDataKeys1_
 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.ArmorTrimMaterial;
 import com.viaversion.viaversion.api.minecraft.item.data.AttackRange;
 import com.viaversion.viaversion.api.minecraft.item.data.AttributeModifiers1_20_5;
 import com.viaversion.viaversion.api.minecraft.item.data.AttributeModifiers1_21;
@@ -47,7 +48,8 @@ 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.DamageResistant1_21_2;
+import com.viaversion.viaversion.api.minecraft.item.data.DamageResistant26_1;
 import com.viaversion.viaversion.api.minecraft.item.data.DamageType;
 import com.viaversion.viaversion.api.minecraft.item.data.DeathProtection;
 import com.viaversion.viaversion.api.minecraft.item.data.DebugStickState;
@@ -65,12 +67,14 @@ 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.JukeboxPlayable.JukeboxSong;
 import com.viaversion.viaversion.api.minecraft.item.data.KineticWeapon;
 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.PiercingWeapon;
 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.ProvidesBannerPatterns;
 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;
@@ -98,8 +102,8 @@ import com.viaversion.viaversion.util.Unit;
  * Holds data component keys.
  *
  * @param identifier string identifier
- * @param type data type
- * @param <T> data type
+ * @param type       data type
+ * @param <T>        data type
  * @see VersionedTypes
  */
 public record StructuredDataKey<T>(String identifier, Type<T> type) {
@@ -113,7 +117,8 @@ public record StructuredDataKey<T>(String identifier, Type<T> 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<Float> MINIMUM_ATTACK_CHARGE = new StructuredDataKey<>("minimum_attack_charge", Types.FLOAT);
-    public static final StructuredDataKey<DamageType> DAMAGE_TYPE = new StructuredDataKey<>("damage_type", DamageType.TYPE);
+    public static final StructuredDataKey<DamageType> DAMAGE_TYPE1_21_11 = new StructuredDataKey<>("damage_type", DamageType.TYPE1_21_11);
+    public static final StructuredDataKey<Integer> DAMAGE_TYPE26_1 = new StructuredDataKey<>("damage_type", new SynchronizedRegistryValueType(RegistryKey.of("damage_type")));
     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));
@@ -142,7 +147,8 @@ public record StructuredDataKey<T>(String identifier, Type<T> type) {
     public static final StructuredDataKey<Consumable1_21_2> CONSUMABLE1_21_2 = new StructuredDataKey<>("consumable", Consumable1_21_2.TYPE);
     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<DamageResistant1_21_2> DAMAGE_RESISTANT1_21_2 = new StructuredDataKey<>("damage_resistant", DamageResistant1_21_2.TYPE);
+    public static final StructuredDataKey<DamageResistant26_1> DAMAGE_RESISTANT26_1 = new StructuredDataKey<>("damage_resistant", DamageResistant26_1.TYPE);
     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);
@@ -155,12 +161,15 @@ public record StructuredDataKey<T>(String identifier, Type<T> type) {
     public static final StructuredDataKey<Unit> GLIDER = new StructuredDataKey<>("glider", Types.EMPTY);
     public static final StructuredDataKey<Key> TOOLTIP_STYLE = new StructuredDataKey<>("tooltip_style", Types.IDENTIFIER);
     public static final StructuredDataKey<DeathProtection> DEATH_PROTECTION = new StructuredDataKey<>("death_protection", DeathProtection.TYPE);
-    public static final StructuredDataKey<BlocksAttacks> BLOCKS_ATTACKS = new StructuredDataKey<>("blocks_attacks", BlocksAttacks.TYPE);
+    public static final StructuredDataKey<BlocksAttacks> BLOCKS_ATTACKS1_21_5 = new StructuredDataKey<>("blocks_attacks", BlocksAttacks.TYPE1_21_5);
+    public static final StructuredDataKey<BlocksAttacks> BLOCKS_ATTACKS26_1 = new StructuredDataKey<>("blocks_attacks", BlocksAttacks.TYPE26_1);
     public static final StructuredDataKey<PiercingWeapon> PIERCING_WEAPON = new StructuredDataKey<>("piercing_weapon", PiercingWeapon.TYPE);
     public static final StructuredDataKey<KineticWeapon> KINETIC_WEAPON = new StructuredDataKey<>("kinetic_weapon", KineticWeapon.TYPE);
     public static final StructuredDataKey<SwingAnimation> SWING_ANIMATION = new StructuredDataKey<>("swing_animation", SwingAnimation.TYPE);
+    public static final StructuredDataKey<Integer> ADDITIONAL_TRADE_COST = new StructuredDataKey<>("additional_trade_cost", Types.VAR_INT);
     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<Integer> DYE = new StructuredDataKey<>("dye", EnumTypes.DYE_COLOR);
     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);
@@ -186,11 +195,15 @@ public record StructuredDataKey<T>(String identifier, Type<T> 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<Holder<Instrument1_21_2>> INSTRUMENT26_1 = new StructuredDataKey<>("instrument", Instrument1_21_2.TYPE);
+    public static final StructuredDataKey<ProvidesTrimMaterial> PROVIDES_TRIM_MATERIAL1_21_5 = new StructuredDataKey<>("provides_trim_material", ProvidesTrimMaterial.TYPE);
+    public static final StructuredDataKey<Holder<ArmorTrimMaterial>> PROVIDES_TRIM_MATERIAL26_1 = new StructuredDataKey<>("provides_trim_material", ArmorTrimMaterial.TYPE1_21_5);
     public static final StructuredDataKey<Integer> OMINOUS_BOTTLE_AMPLIFIER = new StructuredDataKey<>("ominous_bottle_amplifier", Types.VAR_INT);
     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<Holder<JukeboxSong>> JUKEBOX_PLAYABLE26_1 = new StructuredDataKey<>("jukebox_playable", JukeboxSong.TYPE);
+    public static final StructuredDataKey<Key> PROVIDES_BANNER_PATTERNS1_21_5 = new StructuredDataKey<>("provides_banner_patterns", Types.TAG_KEY);
+    public static final StructuredDataKey<ProvidesBannerPatterns> PROVIDES_BANNER_PATTERNS26_1 = new StructuredDataKey<>("provides_banner_patterns", ProvidesBannerPatterns.TYPE);
     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);
@@ -223,8 +236,10 @@ public record StructuredDataKey<T>(String identifier, Type<T> type) {
     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", new SynchronizedRegistryValueType(RegistryKey.of("pig_variant")));
     public static final StructuredDataKey<Integer> COW_VARIANT = new StructuredDataKey<>("cow/variant", new SynchronizedRegistryValueType(RegistryKey.of("cow_variant")));
-    public static final StructuredDataKey<Either<Integer, String>> CHICKEN_VARIANT = new StructuredDataKey<>("chicken/variant", new SynchronizedRegistryEitherType(RegistryKey.of("chicken_variant")));
-    public static final StructuredDataKey<Either<Integer, String>> ZOMBIE_NAUTILUS_VARIANT = new StructuredDataKey<>("zombie_nautilus/variant", new SynchronizedRegistryEitherType(RegistryKey.of("zombie_nautilus_variant"))); // ???
+    public static final StructuredDataKey<Either<Integer, String>> CHICKEN_VARIANT1_21_5 = new StructuredDataKey<>("chicken/variant", new SynchronizedRegistryEitherType(RegistryKey.of("chicken_variant")));
+    public static final StructuredDataKey<Integer> CHICKEN_VARIANT26_1 = new StructuredDataKey<>("chicken/variant", new SynchronizedRegistryValueType(RegistryKey.of("chicken_variant")));
+    public static final StructuredDataKey<Either<Integer, String>> ZOMBIE_NAUTILUS_VARIANT1_21_11 = new StructuredDataKey<>("zombie_nautilus/variant", new SynchronizedRegistryEitherType(RegistryKey.of("zombie_nautilus_variant"))); // ???
+    public static final StructuredDataKey<Integer> ZOMBIE_NAUTILUS_VARIANT26_1 = new StructuredDataKey<>("zombie_nautilus/variant", new SynchronizedRegistryValueType(RegistryKey.of("zombie_nautilus_variant")));
     public static final StructuredDataKey<Integer> FROG_VARIANT = new StructuredDataKey<>("frog/variant", new SynchronizedRegistryValueType(RegistryKey.of("frog_variant")));
     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);
@@ -234,6 +249,10 @@ public record StructuredDataKey<T>(String identifier, Type<T> type) {
     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);
+    public static final StructuredDataKey<Integer> PIG_SOUND_VARIANT = new StructuredDataKey<>("pig/sound_variant", new SynchronizedRegistryValueType(RegistryKey.of("pig_sound_variant")));
+    public static final StructuredDataKey<Integer> COW_SOUND_VARIANT = new StructuredDataKey<>("cow/sound_variant", new SynchronizedRegistryValueType(RegistryKey.of("cow_sound_variant")));
+    public static final StructuredDataKey<Integer> CHICKEN_SOUND_VARIANT = new StructuredDataKey<>("chicken/sound_variant", new SynchronizedRegistryValueType(RegistryKey.of("chicken_sound_variant")));
+    public static final StructuredDataKey<Integer> CAT_SOUND_VARIANT = new StructuredDataKey<>("cat/sound_variant", new SynchronizedRegistryValueType(RegistryKey.of("cat_sound_variant")));
 
     // These are only safe to use after protocol loading
     public static final StructuredDataKeys1_20_5 V1_20_5 = VersionedTypes.V1_20_5.structuredDataKeys();

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

@@ -35,9 +35,9 @@ public class StructuredDataKeys1_21_2 extends VersionedStructuredDataKeys {
     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());
+        this.container = add("container", new ContainerContentsType(types.optionalItemTemplate()));
+        this.chargedProjectiles = add("charged_projectiles", types.itemTemplateArray());
+        this.bundleContents = add("bundle_contents", types.itemTemplateArray());
+        this.useRemainder = add("use_remainder", types.itemTemplate());
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_20_3.java

@@ -33,8 +33,8 @@ public final class EntityDataTypes1_20_3 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType = add(7, Types.ITEM1_20_2);
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

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

@@ -33,8 +33,8 @@ public final class EntityDataTypes1_20_5 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

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

@@ -35,8 +35,8 @@ public final class EntityDataTypes1_21 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes1_21_11.java

@@ -34,8 +34,8 @@ public final class EntityDataTypes1_21_11 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);
@@ -47,7 +47,7 @@ public final class EntityDataTypes1_21_11 extends AbstractEntityDataTypes {
     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 villagerDataType = 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);

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

@@ -35,8 +35,8 @@ public final class EntityDataTypes1_21_2 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

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

@@ -34,8 +34,8 @@ public final class EntityDataTypes1_21_5 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

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

@@ -34,8 +34,8 @@ public final class EntityDataTypes1_21_9 extends AbstractEntityDataTypes {
     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 componentType = add(5, Types.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_OPTIONAL_TAG);
     public final EntityDataType itemType;
     public final EntityDataType booleanType = add(8, Types.BOOLEAN);
     public final EntityDataType rotationsType = add(9, Types.ROTATIONS);

api/src/main/java/com/viaversion/viaversion/api/minecraft/entitydata/types/EntityDataTypes26_1.java

@@ -0,0 +1,82 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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 EntityDataTypes26_1 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.TRUSTED_TAG);
+    public final EntityDataType optionalComponentType = add(6, Types.TRUSTED_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 villagerDataType = 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 catSoundVariant = add(22, Types.VAR_INT);
+    public final EntityDataType cowVariantType = add(23, Types.VAR_INT);
+    public final EntityDataType cowSoundVariant = add(24, Types.VAR_INT);
+    public final EntityDataType wolfVariantType = add(25, Types.VAR_INT);
+    public final EntityDataType wolfSoundVariantType = add(26, Types.VAR_INT);
+    public final EntityDataType frogVariantType = add(27, Types.VAR_INT);
+    public final EntityDataType pigVariantType = add(28, Types.VAR_INT);
+    public final EntityDataType pigSoundVariant = add(29, Types.VAR_INT);
+    public final EntityDataType chickenVariantType = add(30, Types.VAR_INT);
+    public final EntityDataType chickenSoundVariant = add(31, Types.VAR_INT);
+    public final EntityDataType zombieNautilusVariantType = add(32, Types.VAR_INT);
+    public final EntityDataType optionalGlobalPosition = add(33, Types.OPTIONAL_GLOBAL_POSITION);
+    public final EntityDataType paintingVariantType = add(34, PaintingVariant.TYPE1_21_2);
+    public final EntityDataType snifferState = add(35, Types.VAR_INT);
+    public final EntityDataType armadilloState = add(36, Types.VAR_INT);
+    public final EntityDataType copperGolemState = add(37, Types.VAR_INT);
+    public final EntityDataType weatheringCopperState = add(38, Types.VAR_INT);
+    public final EntityDataType vector3FType = add(39, Types.VECTOR3F);
+    public final EntityDataType quaternionType = add(40, Types.QUATERNION);
+    public final EntityDataType mannequinProfileType = add(41, Types.RESOLVABLE_PROFILE);
+    public final EntityDataType humanoidArmType = add(42, Types.VAR_INT);
+
+    public EntityDataTypes26_1(final VersionedTypesHolder types) {
+        super(43);
+        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/Item.java

@@ -76,4 +76,23 @@ public interface Item extends ItemBase {
      */
     @Override
     Item copy();
+
+    /**
+     * Returns whether the item is a template item.
+     *
+     * @return whether the item is a template item
+     */
+    default boolean isTemplate() {
+        return false;
+    }
+
+    /**
+     * Returns whether the item is null or empty.
+     *
+     * @param item item
+     * @return whether the item is null or empty
+     */
+    static boolean isEmpty(@Nullable final Item item) {
+        return item == null || item.isEmpty();
+    }
 }

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

@@ -0,0 +1,59 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataContainer;
+
+public class StructuredItemTemplate extends StructuredItem {
+
+    public StructuredItemTemplate(final int identifier, final int amount) {
+        super(identifier, amount, new StructuredDataContainer());
+    }
+
+    public StructuredItemTemplate(final int identifier, final int amount, final StructuredDataContainer data) {
+        super(identifier, amount, data);
+    }
+
+    @Override
+    public void setIdentifier(final int identifier) {
+        Preconditions.checkArgument(identifier > 0, "Template item cannot be empty");
+        super.setIdentifier(identifier);
+    }
+
+    @Override
+    public void setAmount(final int amount) {
+        Preconditions.checkArgument(amount > 0, "Template item cannot be empty");
+        super.setAmount(amount);
+    }
+
+    @Override
+    public boolean isTemplate() {
+        return true;
+    }
+
+    @Override
+    public StructuredItemTemplate copy() {
+        return new StructuredItemTemplate(identifier(), amount(), dataContainer().copy());
+    }
+}

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

@@ -56,8 +56,8 @@ public record AttackRange(float minRange, float maxRange,
         @Override
         public void write(final Ops ops, final AttackRange AttackRange) {
             ops.writeMap(map -> map
-                .writeOptional("min_range", Types.FLOAT, AttackRange.minRange, 0F)
-                .writeOptional("max_range", Types.FLOAT, AttackRange.maxRange, 3F)
+                .writeOptional("min_reach", Types.FLOAT, AttackRange.minRange, 0F)
+                .writeOptional("max_reach", Types.FLOAT, AttackRange.maxRange, 3F)
                 .writeOptional("min_creative_reach", Types.FLOAT, AttackRange.minCreativeRange, 0F)
                 .writeOptional("max_creative_reach", Types.FLOAT, AttackRange.maxCreativeRange, 5F)
                 .writeOptional("hitbox_margin", Types.FLOAT, AttackRange.hitboxMargin, 0.3F)

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

@@ -37,6 +37,7 @@ import io.netty.buffer.ByteBuf;
 import it.unimi.dsi.fastutil.ints.Int2IntFunction;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean showInTooltip) implements Copyable, Rewritable {
 
@@ -226,7 +227,7 @@ 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 String[] DISPLAY_TYPES = {"default", "hidden", "override"};
         public static final Display DEFAULT = new Display(0);
         private final int id;
 
@@ -246,6 +247,17 @@ public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean show
         public Display copy() {
             return this;
         }
+
+        @Override
+        public boolean equals(final Object o) {
+            if (!(o instanceof final Display display)) return false;
+            return id == display.id;
+        }
+
+        @Override
+        public int hashCode() {
+            return id;
+        }
     }
 
     public static final class OverrideText extends Display {
@@ -271,5 +283,19 @@ public record AttributeModifiers1_21(AttributeModifier[] modifiers, boolean show
         public OverrideText copy() {
             return new OverrideText(this.component.copy());
         }
+
+        @Override
+        public boolean equals(final Object o) {
+            if (!(o instanceof final OverrideText that)) return false;
+            if (!super.equals(o)) return false;
+            return Objects.equals(component, that.component);
+        }
+
+        @Override
+        public int hashCode() {
+            int result = super.hashCode();
+            result = 31 * result + Objects.hashCode(component);
+            return result;
+        }
     }
 }

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

@@ -43,12 +43,12 @@ public record BlocksAttacks(
     float disableCooldownScale,
     DamageReduction[] damageReductions,
     ItemDamageFunction itemDamage,
-    @Nullable String bypassedByTag,
+    @Nullable HolderSet bypassedBy, // always a tag before 26.1
     @Nullable Holder<SoundEvent> blockSound,
     @Nullable Holder<SoundEvent> disableSound
 ) implements Rewritable {
 
-    public static final Type<BlocksAttacks> TYPE = new Type<>(BlocksAttacks.class) {
+    public static final Type<BlocksAttacks> TYPE1_21_5 = new Type<>(BlocksAttacks.class) {
 
         @Override
         public BlocksAttacks read(final ByteBuf buffer) {
@@ -59,7 +59,7 @@ public record BlocksAttacks(
             final String bypassedByTag = Types.OPTIONAL_STRING.read(buffer);
             final Holder<SoundEvent> blockSound = Types.OPTIONAL_SOUND_EVENT.read(buffer);
             final Holder<SoundEvent> disableSound = Types.OPTIONAL_SOUND_EVENT.read(buffer);
-            return new BlocksAttacks(blockDelaySeconds, disableCooldownScale, damageReductions, itemDamage, bypassedByTag, blockSound, disableSound);
+            return new BlocksAttacks(blockDelaySeconds, disableCooldownScale, damageReductions, itemDamage, bypassedByTag != null ? HolderSet.of(bypassedByTag) : null, blockSound, disableSound);
         }
 
         @Override
@@ -68,7 +68,7 @@ public record BlocksAttacks(
             buffer.writeFloat(value.disableCooldownScale());
             DamageReduction.ARRAY_TYPE.write(buffer, value.damageReductions());
             ItemDamageFunction.TYPE.write(buffer, value.itemDamage());
-            Types.OPTIONAL_STRING.write(buffer, value.bypassedByTag());
+            Types.OPTIONAL_STRING.write(buffer, value.bypassedBy() != null ? value.bypassedBy().tagKey() : null);
             Types.OPTIONAL_SOUND_EVENT.write(buffer, value.blockSound());
             Types.OPTIONAL_SOUND_EVENT.write(buffer, value.disableSound());
         }
@@ -82,7 +82,47 @@ public record BlocksAttacks(
                 .writeOptional("disable_cooldown_scale", Types.FLOAT, value.disableCooldownScale(), 1F)
                 .writeOptional("damage_reductions", DamageReduction.ARRAY_TYPE, value.damageReductions(), defaultDamageReductions)
                 .writeOptional("item_damage", ItemDamageFunction.TYPE, value.itemDamage(), defaultItemDamage)
-                .writeOptional("bypassed_by", Types.TAG_KEY, value.bypassedByTag() != null ? Key.of(value.bypassedByTag()) : null)
+                .writeOptional("bypassed_by", Types.TAG_KEY, value.bypassedBy() != null ? Key.of(value.bypassedBy().tagKey()) : null)
+                .writeOptional("block_sound", Types.SOUND_EVENT, value.blockSound())
+                .writeOptional("disabled_sound", Types.SOUND_EVENT, value.disableSound()));
+        }
+    };
+
+    public static final Type<BlocksAttacks> TYPE26_1 = new Type<>(BlocksAttacks.class) {
+
+        @Override
+        public BlocksAttacks read(final ByteBuf buffer) {
+            final float blockDelaySeconds = buffer.readFloat();
+            final float disableCooldownScale = buffer.readFloat();
+            final DamageReduction[] damageReductions = DamageReduction.ARRAY_TYPE.read(buffer);
+            final ItemDamageFunction itemDamage = ItemDamageFunction.TYPE.read(buffer);
+            final HolderSet bypassedByTag = Types.OPTIONAL_HOLDER_SET.read(buffer);
+            final Holder<SoundEvent> blockSound = Types.OPTIONAL_SOUND_EVENT.read(buffer);
+            final Holder<SoundEvent> disableSound = Types.OPTIONAL_SOUND_EVENT.read(buffer);
+            return new BlocksAttacks(blockDelaySeconds, disableCooldownScale, damageReductions, itemDamage, bypassedByTag, blockSound, disableSound);
+        }
+
+        @Override
+        public void write(final ByteBuf buffer, final BlocksAttacks value) {
+            buffer.writeFloat(value.blockDelaySeconds());
+            buffer.writeFloat(value.disableCooldownScale());
+            DamageReduction.ARRAY_TYPE.write(buffer, value.damageReductions());
+            ItemDamageFunction.TYPE.write(buffer, value.itemDamage());
+            Types.OPTIONAL_HOLDER_SET.write(buffer, value.bypassedBy());
+            Types.OPTIONAL_SOUND_EVENT.write(buffer, value.blockSound());
+            Types.OPTIONAL_SOUND_EVENT.write(buffer, value.disableSound());
+        }
+
+        @Override
+        public void write(final Ops ops, final BlocksAttacks value) {
+            final DamageReduction[] defaultDamageReductions = {new DamageReduction(90, null, 0, 1)};
+            final ItemDamageFunction defaultItemDamage = new ItemDamageFunction(1, 0, 1);
+            ops.writeMap(map -> map
+                .writeOptional("block_delay_seconds", Types.FLOAT, value.blockDelaySeconds(), 0F)
+                .writeOptional("disable_cooldown_scale", Types.FLOAT, value.disableCooldownScale(), 1F)
+                .writeOptional("damage_reductions", DamageReduction.ARRAY_TYPE, value.damageReductions(), defaultDamageReductions)
+                .writeOptional("item_damage", ItemDamageFunction.TYPE, value.itemDamage(), defaultItemDamage)
+                .writeOptional("bypassed_by", Types.HOLDER_SET, value.bypassedBy())
                 .writeOptional("block_sound", Types.SOUND_EVENT, value.blockSound())
                 .writeOptional("disabled_sound", Types.SOUND_EVENT, value.disableSound()));
         }
@@ -92,7 +132,7 @@ public record BlocksAttacks(
     public BlocksAttacks rewrite(final UserConnection connection, final Protocol<?, ?, ?, ?> protocol, final boolean clientbound) {
         final Holder<SoundEvent> blockSound = SoundEvent.rewriteHolder(this.blockSound, Rewritable.soundRewriteFunction(protocol, clientbound));
         final Holder<SoundEvent> disableSound = SoundEvent.rewriteHolder(this.disableSound, Rewritable.soundRewriteFunction(protocol, clientbound));
-        return new BlocksAttacks(this.blockDelaySeconds, this.disableCooldownScale, this.damageReductions, this.itemDamage, this.bypassedByTag, blockSound, disableSound);
+        return new BlocksAttacks(this.blockDelaySeconds, this.disableCooldownScale, this.damageReductions, this.itemDamage, this.bypassedBy, blockSound, disableSound);
     }
 
     public record DamageReduction(float horizontalBlockingAngle, @Nullable HolderSet type, float base, float factor) {

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

@@ -59,7 +59,7 @@ public record ChatType(ChatTypeDecoration chatDecoration, ChatTypeDecoration nar
             public ChatTypeDecoration read(final ByteBuf buffer) {
                 final String translationKey = Types.STRING.read(buffer);
                 final int[] parameters = Types.INT_ARRAY_PRIMITIVE.read(buffer);
-                final Tag style = Types.TAG.read(buffer);
+                final Tag style = Types.TRUSTED_TAG.read(buffer);
                 return new ChatTypeDecoration(translationKey, parameters, style);
             }
 
@@ -67,7 +67,7 @@ public record ChatType(ChatTypeDecoration chatDecoration, ChatTypeDecoration nar
             public void write(final ByteBuf buffer, final ChatTypeDecoration value) {
                 Types.STRING.write(buffer, value.translationKey());
                 Types.INT_ARRAY_PRIMITIVE.write(buffer, value.parameters());
-                Types.TAG.write(buffer, value.style());
+                Types.TRUSTED_TAG.write(buffer, value.style());
             }
         };
 

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

@@ -44,7 +44,7 @@ public final class ContainterContents {
             ops.writeList(list -> {
                 for (int i = 0; i < value.length; i++) {
                     final Item item = value[i];
-                    if (item.isEmpty()) {
+                    if (item == null || item.isEmpty()) {
                         continue;
                     }
 

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/DamageResistant1_21_2.java

@@ -28,12 +28,12 @@ import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.util.Key;
 
-public record DamageResistant(Key typesTagKey) {
+public record DamageResistant1_21_2(Key typesTagKey) {
 
-    public static final Type<DamageResistant> TYPE = new TransformingType<>(Types.IDENTIFIER, DamageResistant.class, DamageResistant::new, DamageResistant::typesTagKey) {
+    public static final Type<DamageResistant1_21_2> TYPE = new TransformingType<>(Types.IDENTIFIER, DamageResistant1_21_2.class, DamageResistant1_21_2::new, DamageResistant1_21_2::typesTagKey) {
 
         @Override
-        public void write(final Ops ops, final DamageResistant value) {
+        public void write(final Ops ops, final DamageResistant1_21_2 value) {
             ops.writeMap(map -> map.write("types", Types.TAG_KEY, value.typesTagKey));
         }
     };

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/DamageResistant26_1.java

@@ -0,0 +1,40 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.viaversion.api.minecraft.HolderSet;
+import com.viaversion.viaversion.api.minecraft.codec.Ops;
+import com.viaversion.viaversion.api.type.TransformingType;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.Types;
+
+public record DamageResistant26_1(HolderSet types) {
+
+    public static final Type<DamageResistant26_1> TYPE = new TransformingType<>(Types.HOLDER_SET, DamageResistant26_1.class, DamageResistant26_1::new, DamageResistant26_1::types) {
+
+        @Override
+        public void write(final Ops ops, final DamageResistant26_1 value) {
+            ops.writeMap(map -> map.write("types", Types.HOLDER_SET, value.types));
+        }
+    };
+}

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

@@ -28,7 +28,12 @@ import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.EitherType;
 import com.viaversion.viaversion.util.Either;
 
+/**
+ * 1.21.11-only damage type.
+ *
+ * @param id registry int or string id
+ */
 public record DamageType(Either<Integer, String> id) {
 
-    public static final Type<DamageType> TYPE = TransformingType.of(new EitherType<>(Types.VAR_INT, Types.STRING), DamageType.class, DamageType::new, DamageType::id);
+    public static final Type<DamageType> TYPE1_21_11 = TransformingType.of(new EitherType<>(Types.VAR_INT, Types.STRING), DamageType.class, DamageType::new, DamageType::id);
 }

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

@@ -53,6 +53,6 @@ public final class EnumTypes {
     // Hardcoded registries
     public static final RegistryValueType VILLAGER_TYPE = new RegistryValueType(Key.of("villager_type"), "desert", "jungle", "plains", "savanna", "snow", "swamp", "taiga");
     public static final RegistryValueType POTION = new RegistryValueType(Key.of("potion"), "water", "mundane", "thick", "awkward", "night_vision", "long_night_vision", "invisibility", "long_invisibility", "leaping", "long_leaping", "strong_leaping", "fire_resistance", "long_fire_resistance", "swiftness", "long_swiftness", "strong_swiftness", "slowness", "long_slowness", "strong_slowness", "turtle_master", "long_turtle_master", "strong_turtle_master", "water_breathing", "long_water_breathing", "healing", "strong_healing", "harming", "strong_harming", "poison", "long_poison", "strong_poison", "regeneration", "long_regeneration", "strong_regeneration", "strength", "long_strength", "strong_strength", "weakness", "long_weakness", "luck", "slow_falling", "long_slow_falling", "wind_charged", "weaving", "oozing", "infested");
-    public static final RegistryValueType MOB_EFFECT = new RegistryValueType(Key.of("mob_effect"), "speed", "slowness", "haste", "mining_fatigue", "strength", "instant_health", "instant_damage", "jump_boost", "nausea", "regeneration", "resistance", "fire_resistance", "water_breathing", "invisibility", "blindness", "night_vision", "hunger", "weakness", "poison", "wither", "health_boost", "absorption", "saturation", "glowing", "levitation", "luck", "unluck", "slow_falling", "conduit_power", "dolphins_grace", "bad_omen", "hero_of_the_village", "darkness", "trial_omen", "raid_omen", "wind_charged", "weaving", "oozing", "infested");
+    public static final RegistryValueType MOB_EFFECT = new RegistryValueType(Key.of("mob_effect"), "speed", "slowness", "haste", "mining_fatigue", "strength", "instant_health", "instant_damage", "jump_boost", "nausea", "regeneration", "resistance", "fire_resistance", "water_breathing", "invisibility", "blindness", "night_vision", "hunger", "weakness", "poison", "wither", "health_boost", "absorption", "saturation", "glowing", "levitation", "luck", "unluck", "slow_falling", "conduit_power", "dolphins_grace", "bad_omen", "hero_of_the_village", "darkness", "trial_omen", "raid_omen", "wind_charged", "weaving", "oozing", "infested", "breath_of_the_nautilus");
     public static final RegistryValueType CONSUME_EFFECT = new RegistryValueType(Key.of("consume_effect_type"), "apply_effects", "remove_effects", "clear_all_effects", "teleport_randomly", "play_sound");
 }

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

@@ -0,0 +1,34 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.viaversion.api.minecraft.HolderSet;
+import com.viaversion.viaversion.api.minecraft.RegistryKey;
+import com.viaversion.viaversion.api.type.TransformingType;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.types.misc.HolderSetType;
+
+public record ProvidesBannerPatterns(HolderSet patterns) {
+
+    public static final Type<ProvidesBannerPatterns> TYPE = TransformingType.of(new HolderSetType(RegistryKey.of("banner_pattern")), ProvidesBannerPatterns.class, ProvidesBannerPatterns::new, ProvidesBannerPatterns::patterns);
+}

api/src/main/java/com/viaversion/viaversion/api/platform/ViaInjector.java

@@ -79,7 +79,7 @@ public interface ViaInjector {
     }
 
     /**
-     * Get the name of the encoder for then netty pipeline for this platform.
+     * Get the name of the encoder for the netty pipeline for this platform.
      *
      * @return The name
      */
@@ -88,7 +88,7 @@ public interface ViaInjector {
     }
 
     /**
-     * Get the name of the decoder for then netty pipeline for this platform.
+     * Get the name of the decoder for the netty pipeline for this platform.
      *
      * @return The name
      */

api/src/main/java/com/viaversion/viaversion/api/platform/ViaPlatform.java

@@ -165,6 +165,30 @@ public interface ViaPlatform<T> {
         return false;
     }
 
+    /**
+     * Modify the player details payload before it is sent.
+     * This method allows adding, changing, or removing fields from the payload.
+     * It is only called if {@link ViaVersionConfig#sendPlayerDetails()} is true.
+     *
+     * @param connection The UserConnection
+     * @param payload    The constructed payload to modify
+     */
+    default void modifyPlayerDetails(UserConnection connection, JsonObject payload) {
+        // To be overridden if needed
+    }
+
+    /**
+     * Modify the server details payload before it is sent.
+     * This method allows adding, changing, or removing fields from the payload.
+     * It is only called if {@link ViaVersionConfig#sendServerDetails()} is true.
+     *
+     * @param connection The UserConnection
+     * @param payload    The constructed payload to modify
+     */
+    default void modifyServerDetails(UserConnection connection, JsonObject payload) {
+        // To be overridden if needed
+    }
+
     /**
      * Send a custom payload to from a player to the server.
      *

api/src/main/java/com/viaversion/viaversion/api/protocol/Protocol.java

@@ -68,10 +68,6 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
         registerServerbound(state, packetType.getId(), packetType.getId(), handler, false);
     }
 
-    default void registerServerbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler) {
-        registerServerbound(state, unmappedPacketId, mappedPacketId, handler, false);
-    }
-
     /**
      * Registers a serverbound packet, with id transformation and remapper.
      *
@@ -79,19 +75,17 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
      * @param unmappedPacketId unmapped packet id
      * @param mappedPacketId   mapped packet id
      * @param handler          packet handler
-     * @param override         whether an existing mapper should be overridden
      * @see #registerServerbound(ServerboundPacketType, ServerboundPacketType, PacketHandler, boolean)
      */
+    default void registerServerbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler) {
+        registerServerbound(state, unmappedPacketId, mappedPacketId, handler, false);
+    }
+
+    @Deprecated(forRemoval = true)
     void registerServerbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler, boolean override);
 
     void cancelServerbound(State state, int mappedPacketId);
 
-    default void registerClientbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler) {
-        registerClientbound(state, unmappedPacketId, mappedPacketId, handler, false);
-    }
-
-    void cancelClientbound(State state, int unmappedPacketId);
-
     /**
      * Registers a clientbound packet, with id transformation and remapper.
      *
@@ -99,9 +93,15 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
      * @param unmappedPacketId unmapped packet id
      * @param mappedPacketId   mapped packet id
      * @param handler          packet handler
-     * @param override         whether an existing mapper should be overridden
      * @see #registerClientbound(ClientboundPacketType, ClientboundPacketType, PacketHandler, boolean)
      */
+    default void registerClientbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler) {
+        registerClientbound(state, unmappedPacketId, mappedPacketId, handler, false);
+    }
+
+    void cancelClientbound(State state, int unmappedPacketId);
+
+    @Deprecated(forRemoval = true)
     void registerClientbound(State state, int unmappedPacketId, int mappedPacketId, @Nullable PacketHandler handler, boolean override);
 
     // ---------------------------------------------------------------------------------------
@@ -144,6 +144,7 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
      * @param handler          packet handler
      * @param override         whether an existing mapping should be overridden if present
      */
+    @Deprecated(forRemoval = true)
     void registerClientbound(CU packetType, @Nullable CM mappedPacketType, @Nullable PacketHandler handler, boolean override);
 
     /**
@@ -191,6 +192,7 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
      * @param handler          packet handler
      * @param override         whether an existing mapping should be overridden if present
      */
+    @Deprecated(forRemoval = true)
     void registerServerbound(SU packetType, @Nullable SM mappedPacketType, @Nullable PacketHandler handler, boolean override);
 
     /**
@@ -260,6 +262,22 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
      */
     void appendServerbound(SU type, PacketHandler handler);
 
+    /**
+     * Replaces a clientbound packet type handler with another.
+     *
+     * @param type    clientbound packet type
+     * @param handler packet handler
+     */
+    void replaceClientbound(CU type, @Nullable PacketHandler handler);
+
+    /**
+     * Replaces a serverbound packet type handler with another.
+     *
+     * @param type    serverbound packet type
+     * @param handler packet handler
+     */
+    void replaceServerbound(SU type, @Nullable PacketHandler handler);
+
     /**
      * Transform a packet using this protocol
      *
@@ -441,4 +459,13 @@ public interface Protocol<CU extends ClientboundPacketType, CM extends Clientbou
     default boolean isBaseProtocol() {
         return false;
     }
+
+    /**
+     * Marks this protocol as dependent on another. Before being initialized, it will wait for the dependency's completion.
+     *
+     * @return protocol class to depend on
+     */
+    default @Nullable Class<? extends Protocol<?, ?, ?, ?>> dependsOn() {
+        return null;
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/protocol/ProtocolManager.java

@@ -249,7 +249,17 @@ public interface ProtocolManager {
      *
      * @return true if the executor has now been shut down
      */
-    boolean checkForMappingCompletion();
+    default boolean checkForMappingCompletion() {
+        return checkForMappingCompletion(false);
+    }
+
+    /**
+     * Shuts down the executor and uncaches mappings if all futures have been completed.
+     *
+     * @param propagateErrors whether to propagate errors from the futures to the caller
+     * @return true if the executor has now been shut down
+     */
+    boolean checkForMappingCompletion(boolean propagateErrors);
 
     /**
      * Executes the given runnable asynchronously, adding a {@link CompletableFuture}

api/src/main/java/com/viaversion/viaversion/api/protocol/packet/PacketWrapper.java

@@ -328,6 +328,13 @@ public interface PacketWrapper {
      */
     void resetReader();
 
+    /**
+     * Rewind the reader by the given number of arguments, so they can be read again.
+     *
+     * @param values number of values to add to the reader dequeue again
+     */
+    void rewindReader(int values);
+
     /**
      * Sends this packet to the server.
      * <b>Unlike {@link #sendToServer(Class)}, this method does not handle the pipeline with packet id and data changes.</b>
@@ -382,12 +389,21 @@ public interface PacketWrapper {
      */
     void scheduleSendToServer(Class<? extends Protocol> protocol, boolean skipCurrentPipeline) throws InformativeException;
 
+    /**
+     * Allows running through code that may both read and write data to/from this packet wrapper,
+     * but will no-op any write call.
+     *
+     * @param runnable runnable to do further method calls on this packet wrapper
+     */
+    void consumeReadsOnly(Runnable runnable);
+
     /**
      * Returns the packet type, or null if not transformed or manually unset.
      *
      * @return packet type if set
      */
-    @Nullable PacketType getPacketType();
+    @Nullable
+    PacketType getPacketType();
 
     /**
      * Sets the packet type. If set to null, it will not be written to the buffer with {@link #writeToBuffer(ByteBuf)}.

api/src/main/java/com/viaversion/viaversion/api/protocol/packet/mapping/PacketIdMapping.java

@@ -50,6 +50,11 @@ final class PacketIdMapping implements PacketMapping {
         }
     }
 
+    @Override
+    public void setHandler(@Nullable final PacketHandler handler) {
+        this.handler = handler;
+    }
+
     @Override
     public @Nullable PacketHandler handler() {
         return handler;

api/src/main/java/com/viaversion/viaversion/api/protocol/packet/mapping/PacketMapping.java

@@ -39,6 +39,13 @@ public interface PacketMapping {
      */
     void applyType(PacketWrapper wrapper);
 
+    /**
+     * Replaces the current packet handler.
+     *
+     * @param handler packet transformer
+     */
+    void setHandler(@Nullable PacketHandler handler);
+
     /**
      * Returns a packet transformer to transform a packet from one protocol version to another.
      *

api/src/main/java/com/viaversion/viaversion/api/protocol/packet/mapping/PacketTypeMapping.java

@@ -52,6 +52,11 @@ final class PacketTypeMapping implements PacketMapping {
         }
     }
 
+    @Override
+    public void setHandler(@Nullable final PacketHandler handler) {
+        this.handler = handler;
+    }
+
     @Override
     public @Nullable PacketHandler handler() {
         return handler;

api/src/main/java/com/viaversion/viaversion/api/protocol/version/ProtocolVersion.java

@@ -93,6 +93,7 @@ public class ProtocolVersion implements Comparable<ProtocolVersion> {
     public static final ProtocolVersion v1_21_7 = register(772, "1.21.7-1.21.8", new SubVersionRange("1.21", 7, 8));
     public static final ProtocolVersion v1_21_9 = register(773, "1.21.9-1.21.10", new SubVersionRange("1.21", 9, 10));
     public static final ProtocolVersion v1_21_11 = register(774, "1.21.11");
+    public static final ProtocolVersion v26_1 = register(775, "26.1-26.1.1", new SubVersionRange("26.1", 0, 1));
     public static final ProtocolVersion unknown = new ProtocolVersion(VersionType.SPECIAL, -1, -1, "UNKNOWN", null);
 
     static {

api/src/main/java/com/viaversion/viaversion/api/protocol/version/ProtocolVersionRange.java

@@ -27,9 +27,10 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
- * Wrapper class file for {@link com.google.common.collect.Range} to support multiple ranges. This class is used to
+ * Wrapper class file for {@link Range} to support multiple ranges. This class is used to
  * compare {@link ProtocolVersion} objects.
  */
 public class ProtocolVersionRange {
@@ -43,7 +44,7 @@ public class ProtocolVersionRange {
     }
 
     /**
-     * Returns a range that contains all versions.
+     * Returns a range that contains all versions. Adding new ranges to this range is not supported.
      *
      * @return the range
      */
@@ -159,6 +160,46 @@ public class ProtocolVersionRange {
         return false;
     }
 
+    /**
+     * Gets the minimum version in this range. If there are multiple ranges, the lowest minimum is returned.
+     *
+     * @return the minimum version, or null if there is no minimum
+     */
+    public @Nullable ProtocolVersion getMin() {
+        ProtocolVersion min = null;
+        if (this.ranges != null) {
+            for (Range<ProtocolVersion> range : this.ranges) {
+                if (range.hasLowerBound()) {
+                    ProtocolVersion rangeMin = range.lowerEndpoint();
+                    if (min == null || rangeMin.compareTo(min) < 0) {
+                        min = rangeMin;
+                    }
+                }
+            }
+        }
+        return min;
+    }
+
+    /**
+     * Gets the maximum version in this range. If there are multiple ranges, the highest maximum is returned.
+     *
+     * @return the maximum version, or null if there is no maximum
+     */
+    public @Nullable ProtocolVersion getMax() {
+        ProtocolVersion max = null;
+        if (this.ranges != null) {
+            for (Range<ProtocolVersion> range : this.ranges) {
+                if (range.hasUpperBound()) {
+                    ProtocolVersion rangeMax = range.upperEndpoint();
+                    if (max == null || rangeMax.compareTo(max) > 0) {
+                        max = rangeMax;
+                    }
+                }
+            }
+        }
+        return max;
+    }
+
     @Override
     public String toString() {
         if (this.ranges != null) {
@@ -197,7 +238,7 @@ public class ProtocolVersionRange {
     }
 
     /**
-     * Parses a range from a string.
+     * Parses a range from a string generated by {@link #toString()}.
      *
      * @param str the string
      * @return the range

api/src/main/java/com/viaversion/viaversion/api/rewriter/ComponentRewriter.java

@@ -26,6 +26,7 @@ import com.google.gson.JsonElement;
 import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.Tag;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public interface ComponentRewriter {
@@ -37,4 +38,6 @@ public interface ComponentRewriter {
     JsonElement processText(UserConnection connection, @Nullable String json);
 
     void handleShowItem(UserConnection connection, CompoundTag itemTag);
+
+    void passthroughAndProcess(PacketWrapper wrapper);
 }

api/src/main/java/com/viaversion/viaversion/api/rewriter/EntityRewriter.java

@@ -28,6 +28,7 @@ import com.viaversion.viaversion.api.minecraft.entities.EntityType;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
 import com.viaversion.viaversion.api.protocol.Protocol;
 import java.util.List;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public interface EntityRewriter<T extends Protocol<?, ?, ?, ?>> extends Rewriter<T> {
 
@@ -39,6 +40,11 @@ public interface EntityRewriter<T extends Protocol<?, ?, ?, ?>> extends Rewriter
      */
     EntityType typeFromId(int type);
 
+    default @Nullable EntityType typeFromId(final String type) {
+        final int id = protocol().getMappingData().getEntityMappings().id(type);
+        return id == -1 ? null : typeFromId(id);
+    }
+
     /**
      * Returns the entity type from the given id.
      * From 1.14 and onwards, this is the same exact value as {@link #typeFromId(int)}.

api/src/main/java/com/viaversion/viaversion/api/rewriter/ItemRewriter.java

@@ -102,6 +102,16 @@ public interface ItemRewriter<T extends Protocol<?, ?, ?, ?>> extends Rewriter<T
         return itemArrayType();
     }
 
+    @Nullable
+    default Type<Item> itemTemplateType() {
+        return itemType();
+    }
+
+    @Nullable
+    default Type<Item> mappedItemTemplateType() {
+        return mappedItemType();
+    }
+
     /**
      * Returns the NBT tag name used for storing original item data.
      *

api/src/main/java/com/viaversion/viaversion/api/rewriter/RegistryDataRewriter.java

@@ -22,10 +22,22 @@
  */
 package com.viaversion.viaversion.api.rewriter;
 
+import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.util.KeyMappings;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public interface RegistryDataRewriter {
 
-    @Nullable KeyMappings getMappings(String registryKey);
+    void handle(PacketWrapper wrapper);
+
+    @Nullable
+    KeyMappings getMappings(String registryKey);
+
+    boolean shouldRemoveRegistry(String registryKey);
+
+    boolean hasRegistriesToRemove();
+
+    void updateDialog(UserConnection connection, CompoundTag tag);
 }

api/src/main/java/com/viaversion/viaversion/api/type/Types.java

@@ -103,10 +103,11 @@ import com.viaversion.viaversion.api.type.types.math.BlockPositionType1_8;
 import com.viaversion.viaversion.api.type.types.math.ChunkPositionType;
 import com.viaversion.viaversion.api.type.types.math.EulerAngleType;
 import com.viaversion.viaversion.api.type.types.math.GlobalBlockPositionType;
-import com.viaversion.viaversion.api.type.types.math.MovementVectorType;
+import com.viaversion.viaversion.api.type.types.math.LowPrecisionVectorType;
 import com.viaversion.viaversion.api.type.types.math.QuaternionType;
 import com.viaversion.viaversion.api.type.types.math.Vector3fType;
 import com.viaversion.viaversion.api.type.types.math.VectorType;
+import com.viaversion.viaversion.api.type.types.misc.CompoundTagHolderType;
 import com.viaversion.viaversion.api.type.types.misc.CompoundTagType;
 import com.viaversion.viaversion.api.type.types.misc.GameProfileType;
 import com.viaversion.viaversion.api.type.types.misc.HolderSetType;
@@ -117,8 +118,8 @@ import com.viaversion.viaversion.api.type.types.misc.NamedCompoundTagType;
 import com.viaversion.viaversion.api.type.types.misc.PlayerMessageSignatureType;
 import com.viaversion.viaversion.api.type.types.misc.ProfileKeyType;
 import com.viaversion.viaversion.api.type.types.misc.ProfilePropertyType;
-import com.viaversion.viaversion.api.type.types.misc.SoundEventType;
 import com.viaversion.viaversion.api.type.types.misc.ResolvableProfileType;
+import com.viaversion.viaversion.api.type.types.misc.SoundEventType;
 import com.viaversion.viaversion.api.type.types.misc.TagKeyType;
 import com.viaversion.viaversion.api.type.types.misc.TagType;
 import com.viaversion.viaversion.api.type.types.misc.TextComponentTagType;
@@ -198,19 +199,28 @@ public final class Types {
     public static final Type<Vector> VECTOR = new VectorType();
     public static final Type<Vector3f> VECTOR3F = new Vector3fType();
     public static final Type<Quaternion> QUATERNION = new QuaternionType();
-    public static final Type<Vector3d> MOVEMENT_VECTOR = new MovementVectorType();
+    public static final Type<Vector3d> LOW_PRECISION_VECTOR = new LowPrecisionVectorType();
+    @Deprecated(forRemoval = true)
+    public static final Type<Vector3d> MOVEMENT_VECTOR = LOW_PRECISION_VECTOR;
 
     public static final Type<CompoundTag> NAMED_COMPOUND_TAG = new NamedCompoundTagType();
     public static final Type<CompoundTag> OPTIONAL_NAMED_COMPOUND_TAG = new NamedCompoundTagType.OptionalNamedCompoundTagType();
     public static final Type<CompoundTag[]> NAMED_COMPOUND_TAG_ARRAY = new ArrayType<>(Types.NAMED_COMPOUND_TAG);
     public static final Type<CompoundTag> COMPOUND_TAG = new CompoundTagType();
-    public static final Type<CompoundTag> OPTIONAL_COMPOUND_TAG = new CompoundTagType.OptionalCompoundTagType();
+    public static final Type<CompoundTag> OPTIONAL_COMPOUND_TAG = CompoundTagType.OptionalCompoundTagType.type();
+    public static final HolderType<CompoundTag> TRUSTED_COMPOUND_TAG_HOLDER = new CompoundTagHolderType();
+
     public static final Type<Tag> TAG = new TagType();
     public static final Type<Tag[]> TAG_ARRAY = new ArrayType<>(TAG);
-    public static final Type<Tag> OPTIONAL_TAG = new TagType.OptionalTagType();
+    public static final Type<Tag> OPTIONAL_TAG = TagType.OptionalTagType.type();
     public static final Type<Tag> TEXT_COMPONENT_TAG = new TextComponentTagType(); // only strictly needed for hashing
     public static final Type<Tag> CUSTOM_CLICK_ACTION_TAG = new LengthPrefixedTagType(65536);
 
+    public static final Type<Tag> TRUSTED_TAG = new TagType(false);
+    public static final Type<Tag> TRUSTED_OPTIONAL_TAG = TagType.OptionalTagType.trustedType();
+    public static final Type<CompoundTag> TRUSTED_COMPOUND_TAG = new CompoundTagType(false);
+    public static final Type<CompoundTag> TRUSTED_OPTIONAL_COMPOUND_TAG = CompoundTagType.OptionalCompoundTagType.trustedType();
+
     public static final Type<GlobalBlockPosition> GLOBAL_POSITION = new GlobalBlockPositionType();
     public static final Type<GlobalBlockPosition> OPTIONAL_GLOBAL_POSITION = new GlobalBlockPositionType.OptionalGlobalPositionType();
     public static final Type<ChunkPosition> CHUNK_POSITION = new ChunkPositionType();

api/src/main/java/com/viaversion/viaversion/api/type/types/VarIntArrayType.java

@@ -28,13 +28,21 @@ import com.viaversion.viaversion.api.type.Types;
 import io.netty.buffer.ByteBuf;
 
 public class VarIntArrayType extends Type<int[]> {
-    public VarIntArrayType() {
+
+    private final int length;
+
+    public VarIntArrayType(final int length) {
         super(int[].class);
+        this.length = length;
+    }
+
+    public VarIntArrayType() {
+        this(-1);
     }
 
     @Override
     public int[] read(ByteBuf buffer) {
-        int length = Types.VAR_INT.readPrimitive(buffer);
+        int length = this.length == -1 ? Types.VAR_INT.readPrimitive(buffer) : this.length;
         Preconditions.checkArgument(buffer.isReadable(length)); // Sanity check, at least 1 byte will be used for each varint
         int[] array = new int[length];
         for (int i = 0; i < array.length; i++) {
@@ -45,7 +53,11 @@ public class VarIntArrayType extends Type<int[]> {
 
     @Override
     public void write(ByteBuf buffer, int[] object) {
-        Types.VAR_INT.writePrimitive(buffer, object.length);
+        if (this.length != -1) {
+            Preconditions.checkArgument(length == object.length, "Length does not match expected length");
+        } else {
+            Types.VAR_INT.writePrimitive(buffer, object.length);
+        }
         for (int i : object) {
             Types.VAR_INT.writePrimitive(buffer, i);
         }

api/src/main/java/com/viaversion/viaversion/api/type/types/chunk/ChunkSectionType1_18.java

@@ -31,8 +31,8 @@ import io.netty.buffer.ByteBuf;
 
 public class ChunkSectionType1_18 extends Type<ChunkSection> {
 
-    private final PaletteTypeBase blockPaletteType;
-    private final PaletteTypeBase biomePaletteType;
+    protected final PaletteTypeBase blockPaletteType;
+    protected final PaletteTypeBase biomePaletteType;
 
     public ChunkSectionType1_18(final int globalPaletteBlockBits, final int globalPaletteBiomeBits) {
         super(ChunkSection.class);

api/src/main/java/com/viaversion/viaversion/api/type/types/chunk/ChunkSectionType26_1.java

@@ -0,0 +1,68 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.type.types.chunk;
+
+import com.viaversion.viaversion.api.minecraft.chunks.Chunk;
+import com.viaversion.viaversion.api.minecraft.chunks.ChunkSection;
+import com.viaversion.viaversion.api.minecraft.chunks.ChunkSectionImpl;
+import com.viaversion.viaversion.api.minecraft.chunks.PaletteType;
+import io.netty.buffer.ByteBuf;
+
+public class ChunkSectionType26_1 extends ChunkSectionType1_18 {
+
+    public ChunkSectionType26_1(final int globalPaletteBlockBits, final int globalPaletteBiomeBits) {
+        super(
+            new PaletteType1_21_5(PaletteType.BLOCKS, globalPaletteBlockBits),
+            new PaletteType1_21_5(PaletteType.BIOMES, globalPaletteBiomeBits)
+        );
+    }
+
+    @Override
+    public ChunkSection read(final ByteBuf buffer) {
+        final ChunkSection chunkSection = new ChunkSectionImpl();
+        chunkSection.setNonAirBlocksCount(buffer.readShort());
+        chunkSection.setFluidCount(buffer.readShort());
+        chunkSection.addPalette(PaletteType.BLOCKS, blockPaletteType.read(buffer));
+        chunkSection.addPalette(PaletteType.BIOMES, biomePaletteType.read(buffer));
+        return chunkSection;
+    }
+
+    @Override
+    public void write(final ByteBuf buffer, final ChunkSection section) {
+        buffer.writeShort(section.getNonAirBlocksCount());
+        buffer.writeShort(section.getFluidCount());
+        blockPaletteType.write(buffer, section.palette(PaletteType.BLOCKS));
+        biomePaletteType.write(buffer, section.palette(PaletteType.BIOMES));
+    }
+
+    @Override
+    public int serializedSize(final Chunk chunk) {
+        int length = 0;
+        for (final ChunkSection section : chunk.getSections()) {
+            length += Short.BYTES + Short.BYTES // non-air and fluid count
+                + blockPaletteType.serializedSize(section.palette(PaletteType.BLOCKS))
+                + biomePaletteType.serializedSize(section.palette(PaletteType.BIOMES));
+        }
+        return length;
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/type/types/chunk/ChunkType1_21_5.java

@@ -34,14 +34,18 @@ import io.netty.buffer.ByteBuf;
 import java.util.ArrayList;
 import java.util.List;
 
-public final class ChunkType1_21_5 extends Type<Chunk> {
+public class ChunkType1_21_5 extends Type<Chunk> {
     private final ChunkSectionType1_18 sectionType;
     private final int ySectionCount;
 
     public ChunkType1_21_5(final int ySectionCount, final int globalPaletteBlockBits, final int globalPaletteBiomeBits) {
+        this(new ChunkSectionType1_21_5(globalPaletteBlockBits, globalPaletteBiomeBits), ySectionCount);
+    }
+
+    protected ChunkType1_21_5(final ChunkSectionType1_18 sectionType, final int ySectionCount) {
         super(Chunk.class);
         Preconditions.checkArgument(ySectionCount > 0);
-        this.sectionType = new ChunkSectionType1_21_5(globalPaletteBlockBits, globalPaletteBiomeBits);
+        this.sectionType = sectionType;
         this.ySectionCount = ySectionCount;
     }
 

api/src/main/java/com/viaversion/viaversion/api/type/types/chunk/ChunkType26_1.java

@@ -20,17 +20,11 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-package com.viaversion.viaversion.api.protocol;
+package com.viaversion.viaversion.api.type.types.chunk;
 
-/**
- * A simple protocol which does not have any packet types.
- * <p>
- * {@link AbstractProtocol} should be preferred over this class in most cases.
- */
-public abstract class AbstractSimpleProtocol extends AbstractProtocol<SimpleProtocol.DummyPacketTypes, SimpleProtocol.DummyPacketTypes,
-    SimpleProtocol.DummyPacketTypes, SimpleProtocol.DummyPacketTypes> implements SimpleProtocol {
+public final class ChunkType26_1 extends ChunkType1_21_5 {
 
-    protected AbstractSimpleProtocol() {
-        super(null, null, null, null);
+    public ChunkType26_1(final int ySectionCount, final int globalPaletteBlockBits, final int globalPaletteBiomeBits) {
+        super(new ChunkSectionType26_1(globalPaletteBlockBits, globalPaletteBiomeBits), ySectionCount);
     }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/item/ItemTemplateType26_1.java

@@ -0,0 +1,64 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.type.types.item;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredData;
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataContainer;
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataKey;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.minecraft.item.StructuredItemTemplate;
+import com.viaversion.viaversion.api.type.OptionalType;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.Types;
+import io.netty.buffer.ByteBuf;
+import java.util.Map;
+
+// Holds the same exact data as a regular item stack
+public class ItemTemplateType26_1 extends ItemType1_20_5 {
+
+    public ItemTemplateType26_1(final StructuredDataTypeBase dataType) {
+        super(dataType);
+    }
+
+    @Override
+    public Item read(final ByteBuf buffer) {
+        final int id = Types.VAR_INT.readPrimitive(buffer);
+        final int amount = Types.VAR_INT.readPrimitive(buffer);
+        final Map<StructuredDataKey<?>, StructuredData<?>> data = readData(buffer);
+        return new StructuredItemTemplate(id, amount, new StructuredDataContainer(data));
+    }
+
+    @Override
+    public void write(final ByteBuf buffer, final Item object) {
+        Types.VAR_INT.writePrimitive(buffer, object.identifier());
+        Types.VAR_INT.writePrimitive(buffer, object.amount());
+        writeData(buffer, object);
+    }
+
+    public static final class OptionalItemTemplateType extends OptionalType<Item> {
+
+        public OptionalItemTemplateType(final Type<Item> type) {
+            super(type);
+        }
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/type/types/item/ItemType1_20_5.java

@@ -58,7 +58,7 @@ public class ItemType1_20_5 extends Type<Item> {
         return new StructuredItem(id, amount, new StructuredDataContainer(data));
     }
 
-    private Map<StructuredDataKey<?>, StructuredData<?>> readData(final ByteBuf buffer) {
+    protected Map<StructuredDataKey<?>, StructuredData<?>> readData(final ByteBuf buffer) {
         final int valuesSize = Types.VAR_INT.readPrimitive(buffer);
         final int markersSize = Types.VAR_INT.readPrimitive(buffer);
         if (valuesSize == 0 && markersSize == 0) {
@@ -92,6 +92,10 @@ public class ItemType1_20_5 extends Type<Item> {
         Types.VAR_INT.writePrimitive(buffer, object.amount());
         Types.VAR_INT.writePrimitive(buffer, object.identifier());
 
+        writeData(buffer, object);
+    }
+
+    protected void writeData(final ByteBuf buffer, final Item object) {
         final Map<StructuredDataKey<?>, StructuredData<?>> data = object.dataContainer().data();
         int valuesSize = 0;
         int markersSize = 0;

api/src/main/java/com/viaversion/viaversion/api/type/types/math/LowPrecisionVectorType.java

@@ -29,7 +29,7 @@ import com.viaversion.viaversion.api.type.types.UnsignedIntType;
 import com.viaversion.viaversion.util.MathUtil;
 import io.netty.buffer.ByteBuf;
 
-public class MovementVectorType extends Type<Vector3d> {
+public class LowPrecisionVectorType extends Type<Vector3d> {
     // Using 15 bits, steal short constants for it
     private static final double MAX_QUANTIZED_VALUE = Short.MAX_VALUE - 1;
     private static final int SCALE_BITS = 2; // first 2 bits for the scale
@@ -38,7 +38,7 @@ public class MovementVectorType extends Type<Vector3d> {
     private static final double ABS_MAX_VALUE = (1L << Integer.SIZE + SCALE_BITS) - 1; // Unsigned int + the first two scale bits
     private static final double ABS_MIN_VALUE = 1 / MAX_QUANTIZED_VALUE;
 
-    public MovementVectorType() {
+    public LowPrecisionVectorType() {
         super(Vector3d.class);
     }
 

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/CompoundTagHolderType.java

@@ -0,0 +1,40 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.type.types.misc;
+
+import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.viaversion.api.type.Types;
+import io.netty.buffer.ByteBuf;
+
+public final class CompoundTagHolderType extends HolderType<CompoundTag> {
+
+    @Override
+    public CompoundTag readDirect(final ByteBuf buffer) {
+        return Types.TRUSTED_COMPOUND_TAG.read(buffer);
+    }
+
+    @Override
+    public void writeDirect(final ByteBuf buffer, final CompoundTag value) {
+        Types.TRUSTED_COMPOUND_TAG.write(buffer, value);
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/CompoundTagType.java

@@ -41,14 +41,21 @@ import java.util.Map;
  */
 public class CompoundTagType extends Type<CompoundTag> {
 
+    private final int maxBytes;
+
     public CompoundTagType() {
+        this(true);
+    }
+
+    public CompoundTagType(final boolean limitMaxBytes) {
         super(CompoundTag.class);
+        this.maxBytes = limitMaxBytes ? NamedCompoundTagType.MAX_NBT_BYTES : Integer.MAX_VALUE;
     }
 
     @Override
     public CompoundTag read(final ByteBuf buffer) {
         try {
-            return NamedCompoundTagType.read(buffer, false);
+            return NamedCompoundTagType.read(buffer, this.maxBytes, false);
         } catch (final IOException e) {
             throw new RuntimeException(e);
         }
@@ -74,8 +81,16 @@ public class CompoundTagType extends Type<CompoundTag> {
 
     public static final class OptionalCompoundTagType extends OptionalType<CompoundTag> {
 
-        public OptionalCompoundTagType() {
-            super(Types.COMPOUND_TAG);
+        private OptionalCompoundTagType(final Type<CompoundTag> tagType) {
+            super(tagType);
+        }
+
+        public static OptionalCompoundTagType type() {
+            return new OptionalCompoundTagType(Types.COMPOUND_TAG);
+        }
+
+        public static OptionalCompoundTagType trustedType() {
+            return new OptionalCompoundTagType(Types.TRUSTED_COMPOUND_TAG);
         }
     }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/EitherHolderType.java

@@ -29,6 +29,11 @@ import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.util.Key;
 import io.netty.buffer.ByteBuf;
 
+/**
+ * Mess for certain pre 26.1 things.
+ *
+ * @param <T> held type
+ */
 public final class EitherHolderType<T> extends Type<EitherHolder<T>> {
     private final HolderType<T> holderType;
 

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/HolderSetType.java

@@ -30,6 +30,7 @@ import com.viaversion.viaversion.api.minecraft.codec.Ops;
 import com.viaversion.viaversion.api.type.OptionalType;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
+import com.viaversion.viaversion.api.type.types.VarIntArrayType;
 import com.viaversion.viaversion.util.Key;
 import io.netty.buffer.ByteBuf;
 
@@ -58,12 +59,7 @@ public class HolderSetType extends Type<HolderSet> {
             final String tag = Types.STRING.read(buffer);
             return HolderSet.of(tag);
         }
-
-        final int[] values = new int[size];
-        for (int i = 0; i < size; i++) {
-            values[i] = Types.VAR_INT.readPrimitive(buffer);
-        }
-        return HolderSet.of(values);
+        return HolderSet.of(new VarIntArrayType(size).read(buffer));
     }
 
     @Override

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/NamedCompoundTagType.java

@@ -46,7 +46,7 @@ public class NamedCompoundTagType extends Type<CompoundTag> {
     @Override
     public CompoundTag read(final ByteBuf buffer) {
         try {
-            return read(buffer, true);
+            return read(buffer, MAX_NBT_BYTES, true);
         } catch (final IOException e) {
             throw new RuntimeException(e);
         }
@@ -61,7 +61,7 @@ public class NamedCompoundTagType extends Type<CompoundTag> {
         }
     }
 
-    public static CompoundTag read(final ByteBuf buffer, final boolean readName) throws IOException {
+    public static CompoundTag read(final ByteBuf buffer, final int maxBytes, final boolean readName) throws IOException {
         final byte id = buffer.readByte();
         if (id == 0) {
             return null;
@@ -74,7 +74,7 @@ public class NamedCompoundTagType extends Type<CompoundTag> {
             buffer.skipBytes(buffer.readUnsignedShort());
         }
 
-        final TagLimiter tagLimiter = TagLimiter.create(MAX_NBT_BYTES, MAX_NESTING_LEVEL);
+        final TagLimiter tagLimiter = TagLimiter.create(maxBytes, MAX_NESTING_LEVEL);
         return CompoundTag.read(new ByteBufInputStream(buffer), tagLimiter, 0);
     }
 

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/ParticleType.java

@@ -59,17 +59,13 @@ public class ParticleType extends DynamicType<Particle> {
         return protocol.getMappingData().getParticleMappings();
     }
 
-    public static DataReader<Particle> itemHandler(final Type<Item> itemType) {
-        return (buf, particle) -> particle.add(itemType, itemType.read(buf));
-    }
-
     public static final class Readers {
 
         public static final DataReader<Particle> BLOCK = (buf, particle) -> {
             particle.add(Types.VAR_INT, Types.VAR_INT.readPrimitive(buf)); // Flat Block
         };
-        public static final DataReader<Particle> ITEM1_13 = itemHandler(Types.ITEM1_13);
-        public static final DataReader<Particle> ITEM1_13_2 = itemHandler(Types.ITEM1_13_2);
+        public static final DataReader<Particle> ITEM1_13 = item(Types.ITEM1_13);
+        public static final DataReader<Particle> ITEM1_13_2 = item(Types.ITEM1_13_2);
         public static final DataReader<Particle> DUST = (buf, particle) -> {
             particle.add(Types.FLOAT, Types.FLOAT.readPrimitive(buf)); // Red 0-1
             particle.add(Types.FLOAT, Types.FLOAT.readPrimitive(buf)); // Green 0-1
@@ -172,4 +168,103 @@ public class ParticleType extends DynamicType<Particle> {
             return (buf, particle) -> particle.add(item, item.read(buf));
         }
     }
+
+    public static final class Fillers {
+
+        public static DynamicType<Particle>.DataFiller fill1_13_2(final Protocol<?, ?, ?, ?> protocol, final ParticleType type, final boolean useMappedNames) {
+            return type.filler(protocol, useMappedNames)
+                .reader("item", Readers.item(protocol.getItemRewriter().mappedItemType()))
+                .reader("block", Readers.BLOCK)
+                .reader("dust", Readers.DUST)
+                .reader("falling_dust", Readers.BLOCK);
+        }
+
+        public static DataFiller fill1_17(final Protocol<?, ?, ?, ?> protocol, final ParticleType type) {
+            return fill1_13_2(protocol, type, true)
+                .reader("dust_color_transition", Readers.DUST_TRANSITION)
+                .reader("vibration", Readers.VIBRATION);
+        }
+
+        public static void fill1_18(final Protocol<?, ?, ?, ?> protocol, final ParticleType type) {
+            fill1_17(protocol, type).reader("block_marker", Readers.BLOCK);
+        }
+
+        public static void fill1_19(final Protocol<?, ?, ?, ?> protocol, final ParticleType type) {
+            type.filler(protocol)
+                .reader("item", Readers.item(protocol.getItemRewriter().mappedItemType()))
+                .reader("block", Readers.BLOCK)
+                .reader("block_marker", Readers.BLOCK)
+                .reader("dust", Readers.DUST)
+                .reader("falling_dust", Readers.BLOCK)
+                .reader("dust_color_transition", Readers.DUST_TRANSITION)
+                .reader("vibration", Readers.VIBRATION1_19)
+                .reader("sculk_charge", Readers.SCULK_CHARGE)
+                .reader("shriek", Readers.SHRIEK);
+        }
+
+        public static DataFiller fill1_20_3(final Protocol<?, ?, ?, ?> protocol, final ParticleType type) {
+            return type.filler(protocol)
+                .reader("item", Readers.item(protocol.getItemRewriter().mappedItemType()))
+                .reader("block", Readers.BLOCK)
+                .reader("block_marker", Readers.BLOCK)
+                .reader("dust", Readers.DUST)
+                .reader("falling_dust", Readers.BLOCK)
+                .reader("dust_color_transition", Readers.DUST_TRANSITION)
+                .reader("vibration", Readers.VIBRATION1_20_3)
+                .reader("sculk_charge", Readers.SCULK_CHARGE)
+                .reader("shriek", Readers.SHRIEK);
+        }
+
+        public static void fill1_20_5(final Protocol<?, ?, ?, ?> protocol, final ParticleType type) {
+            fill1_20_3(protocol, type)
+                .reader("dust_pillar", Readers.BLOCK)
+                .reader("entity_effect", Readers.COLOR);
+        }
+
+        public static void fill1_21_2(final Protocol<?, ?, ?, ?> protocol) {
+            protocol.mappedTypes().particle().filler(protocol)
+                .reader("item", Readers.item(protocol.getItemRewriter().mappedItemType()))
+                .reader("block", Readers.BLOCK)
+                .reader("block_marker", Readers.BLOCK)
+                .reader("dust_pillar", Readers.BLOCK)
+                .reader("falling_dust", Readers.BLOCK)
+                .reader("block_crumble", Readers.BLOCK)
+                .reader("dust", Readers.DUST1_21_2)
+                .reader("dust_color_transition", Readers.DUST_TRANSITION1_21_2)
+                .reader("vibration", Readers.VIBRATION1_20_3)
+                .reader("sculk_charge", Readers.SCULK_CHARGE)
+                .reader("shriek", Readers.SHRIEK)
+                .reader("entity_effect", Readers.COLOR)
+                .reader("trail", Readers.TRAIL1_21_2);
+        }
+
+        public static DataFiller fill1_21_4(final Protocol<?, ?, ?, ?> protocol) {
+            return protocol.mappedTypes().particle().filler(protocol)
+                .reader("item", Readers.item(protocol.getItemRewriter().mappedItemTemplateType()))
+                .reader("block", Readers.BLOCK)
+                .reader("block_marker", Readers.BLOCK)
+                .reader("dust_pillar", Readers.BLOCK)
+                .reader("falling_dust", Readers.BLOCK)
+                .reader("block_crumble", Readers.BLOCK)
+                .reader("dust", Readers.DUST1_21_2)
+                .reader("dust_color_transition", Readers.DUST_TRANSITION1_21_2)
+                .reader("vibration", Readers.VIBRATION1_20_3)
+                .reader("sculk_charge", Readers.SCULK_CHARGE)
+                .reader("shriek", Readers.SHRIEK)
+                .reader("entity_effect", Readers.COLOR)
+                .reader("trail", Readers.TRAIL1_21_4);
+        }
+
+        public static DataFiller fill1_21_5(final Protocol<?, ?, ?, ?> protocol) {
+            return fill1_21_4(protocol).reader("tinted_leaves", Readers.COLOR);
+        }
+
+        public static void fill1_21_9(final Protocol<?, ?, ?, ?> protocol) {
+            fill1_21_5(protocol)
+                .reader("dragon_breath", Readers.POWER)
+                .reader("effect", Readers.SPELL)
+                .reader("instant_effect", Readers.SPELL)
+                .reader("flash", Readers.COLOR);
+        }
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/misc/TagType.java

@@ -50,8 +50,15 @@ import java.util.Map;
 
 public class TagType extends Type<Tag> {
 
+    private final int maxBytes;
+
     public TagType() {
+        this(true);
+    }
+
+    public TagType(final boolean limitBytes) {
         super(Tag.class);
+        this.maxBytes = limitBytes ? NamedCompoundTagType.MAX_NBT_BYTES : Integer.MAX_VALUE;
     }
 
     @Override
@@ -61,7 +68,7 @@ public class TagType extends Type<Tag> {
             return null;
         }
 
-        final TagLimiter tagLimiter = TagLimiter.create(NamedCompoundTagType.MAX_NBT_BYTES, NamedCompoundTagType.MAX_NESTING_LEVEL);
+        final TagLimiter tagLimiter = TagLimiter.create(this.maxBytes, NamedCompoundTagType.MAX_NESTING_LEVEL);
         try {
             return TagRegistry.read(id, new ByteBufInputStream(buffer), tagLimiter, 0);
         } catch (final IOException e) {
@@ -127,8 +134,16 @@ public class TagType extends Type<Tag> {
 
     public static final class OptionalTagType extends OptionalType<Tag> {
 
-        public OptionalTagType() {
-            super(Types.TAG);
+        private OptionalTagType(final Type<Tag> tagType) {
+            super(tagType);
+        }
+
+        public static OptionalTagType type() {
+            return new OptionalTagType(Types.TAG);
+        }
+
+        public static OptionalTagType trustedType() {
+            return new OptionalTagType(Types.TRUSTED_TAG);
         }
     }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/version/Types1_20_5.java

@@ -50,7 +50,7 @@ public class Types1_20_5<K extends VersionedStructuredDataKeys, E extends Abstra
     public final Type<Item[]> itemArray = new ArrayType<>(item);
     public final Type<Item> itemCost = new ItemCostType1_20_5(structuredDataArray);
     public final Type<Item> optionalItemCost = new ItemCostType1_20_5.OptionalItemCostType(itemCost);
-    public final K structuredDataKeys;
+    private K structuredDataKeys;
 
     public final ParticleType particle = new ParticleType();
     public final ArrayType<Particle> particles = new ArrayType<>(particle);
@@ -58,11 +58,17 @@ public class Types1_20_5<K extends VersionedStructuredDataKeys, E extends Abstra
     public final Type<EntityData> entityData;
     public final Type<List<EntityData>> entityDataList;
 
-    public Types1_20_5(final Function<Types1_20_5<?, ?>, K> keysSupplier, final Function<Types1_20_5<?, ?>, E> entityDataTypesSupplier) {
-        this.structuredDataKeys = keysSupplier.apply(this);
+    public Types1_20_5(final Function<VersionedTypesHolder, K> keysSupplier, final Function<VersionedTypesHolder, E> entityDataTypesSupplier) {
         this.entityDataTypes = entityDataTypesSupplier.apply(this);
         this.entityData = new EntityDataType(entityDataTypes);
         this.entityDataList = new EntityDataListType(entityData);
+        if (keysSupplier != null) {
+            initKeys(keysSupplier);
+        }
+    }
+
+    protected void initKeys(final Function<VersionedTypesHolder, K> keysSupplier) {
+        this.structuredDataKeys = keysSupplier.apply(this);
     }
 
     @Override
@@ -75,6 +81,21 @@ public class Types1_20_5<K extends VersionedStructuredDataKeys, E extends Abstra
         return itemArray;
     }
 
+    @Override
+    public Type<Item> itemTemplate() {
+        return item;
+    }
+
+    @Override
+    public Type<Item> optionalItemTemplate() {
+        return item;
+    }
+
+    @Override
+    public Type<Item[]> itemTemplateArray() {
+        return itemArray;
+    }
+
     @Override
     public Type<Item> itemCost() {
         return itemCost;

api/src/main/java/com/viaversion/viaversion/api/type/types/version/Types1_21.java

@@ -34,7 +34,7 @@ public final class Types1_21 extends Types1_20_5<StructuredDataKeys1_20_5, Entit
 
     public final Type<Item> optionalItem; // Optional as in boolean prefixed, not via the amount
 
-    public Types1_21(final Function<Types1_20_5<?, ?>, StructuredDataKeys1_20_5> keysSupplier, final Function<Types1_20_5<?, ?>, EntityDataTypes1_21> entityDataTypesSupplier) {
+    public Types1_21(final Function<VersionedTypesHolder, StructuredDataKeys1_20_5> keysSupplier, final Function<VersionedTypesHolder, EntityDataTypes1_21> entityDataTypesSupplier) {
         super(keysSupplier, entityDataTypesSupplier);
         this.optionalItem = ((ItemType1_20_5) item).new OptionalItemType();
     }

api/src/main/java/com/viaversion/viaversion/api/type/types/version/Types26_1.java

@@ -0,0 +1,58 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 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.type.types.version;
+
+import com.viaversion.viaversion.api.minecraft.data.version.VersionedStructuredDataKeys;
+import com.viaversion.viaversion.api.minecraft.entitydata.types.AbstractEntityDataTypes;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.api.type.types.item.ItemTemplateType26_1;
+import java.util.function.Function;
+
+public class Types26_1<K extends VersionedStructuredDataKeys, E extends AbstractEntityDataTypes> extends Types1_20_5<K, E> {
+
+    public final Type<Item> itemTemplate = new ItemTemplateType26_1(structuredData);
+    public final Type<Item> optionalItemTemplate = new ItemTemplateType26_1.OptionalItemTemplateType(itemTemplate);
+    public final Type<Item[]> itemTemplateArray = new ArrayType<>(itemTemplate);
+
+    public Types26_1(final Function<VersionedTypesHolder, K> keysSupplier, final Function<VersionedTypesHolder, E> entityDataTypesSupplier) {
+        super(null, entityDataTypesSupplier);
+        initKeys(keysSupplier);
+    }
+
+    @Override
+    public Type<Item> itemTemplate() {
+        return itemTemplate;
+    }
+
+    @Override
+    public Type<Item> optionalItemTemplate() {
+        return optionalItemTemplate;
+    }
+
+    @Override
+    public Type<Item[]> itemTemplateArray() {
+        return itemTemplateArray;
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/type/types/version/VersionedTypes.java

@@ -32,6 +32,7 @@ import com.viaversion.viaversion.api.minecraft.entitydata.types.EntityDataTypes1
 import com.viaversion.viaversion.api.minecraft.entitydata.types.EntityDataTypes1_21_2;
 import com.viaversion.viaversion.api.minecraft.entitydata.types.EntityDataTypes1_21_5;
 import com.viaversion.viaversion.api.minecraft.entitydata.types.EntityDataTypes1_21_9;
+import com.viaversion.viaversion.api.minecraft.entitydata.types.EntityDataTypes26_1;
 
 /**
  * Holds versioned accessors for highly volatile types, specifically around items and data components.
@@ -49,4 +50,5 @@ public final class VersionedTypes {
     public static final Types1_20_5<StructuredDataKeys1_21_5, EntityDataTypes1_21_5> V1_21_6 = new Types1_20_5<>(StructuredDataKeys1_21_5::new, EntityDataTypes1_21_5::new);
     public static final Types1_20_5<StructuredDataKeys1_21_5, EntityDataTypes1_21_9> V1_21_9 = new Types1_20_5<>(StructuredDataKeys1_21_5::new, EntityDataTypes1_21_9::new);
     public static final Types1_20_5<StructuredDataKeys1_21_11, EntityDataTypes1_21_11> V1_21_11 = new Types1_20_5<>(StructuredDataKeys1_21_11::new, EntityDataTypes1_21_11::new);
+    public static final Types26_1<StructuredDataKeys1_21_11, EntityDataTypes26_1> V26_1 = new Types26_1<>(StructuredDataKeys1_21_11::new, EntityDataTypes26_1::new);
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/version/VersionedTypesHolder.java

@@ -39,10 +39,31 @@ import java.util.List;
  */
 public interface VersionedTypesHolder {
 
+    /**
+     * Returns the unmapped item stack type
+     *
+     * @return unmapped item stack type
+     */
     Type<Item> item();
 
     Type<Item[]> itemArray();
 
+    /**
+     * Returns the unmapped item stack template type, used for certain recipes/templates in 26.1+.
+     *
+     * @return unmapped item stack template type
+     */
+    Type<Item> itemTemplate();
+
+    Type<Item> optionalItemTemplate();
+
+    Type<Item[]> itemTemplateArray();
+
+    /**
+     * Returns the unmapped item cost type, used in merchant offers.
+     *
+     * @return unmapped item cost type
+     */
     Type<Item> itemCost();
 
     Type<Item> optionalItemCost();

api/src/main/java/com/viaversion/viaversion/exception/InformativeException.java

@@ -60,7 +60,7 @@ public class InformativeException extends RuntimeException {
 
     @Override
     public String getMessage() {
-        final StringBuilder builder = new StringBuilder("Please report this on the Via support Discord or open an issue on the relevant GitHub repository\n");
+        final StringBuilder builder = new StringBuilder("Please report the full error (!) from the console on the Via support Discord or open an issue on the relevant GitHub repository.\n");
         boolean first = true;
         for (final DataEntry entry : dataEntries) {
             if (!first) {

build-logic/build.gradle.kts

@@ -8,7 +8,7 @@ repositories {
 
 dependencies {
     // version must be manually kept in sync with the one in root project settings.gradle.kts
-    implementation("com.gradleup.shadow:shadow-gradle-plugin:9.3.1")
+    implementation("com.gradleup.shadow:shadow-gradle-plugin:9.4.1")
 
     // A nice no-conflict comment for patching in downgrading
 }

bukkit-legacy/src/main/java/com/viaversion/viaversion/bukkit/util/NMSUtil.java

@@ -49,6 +49,20 @@ public final class NMSUtil {
         }
     }
 
+    public static Class<?> nms(String className, String... fallbackFullClassNames) throws ClassNotFoundException {
+        try {
+            return Class.forName(NMS + "." + className);
+        } catch (ClassNotFoundException ignored) {
+        }
+        for (final String fallbackFullClassName : fallbackFullClassNames) {
+            try {
+                return Class.forName(fallbackFullClassName);
+            } catch (ClassNotFoundException ignored) {
+            }
+        }
+        throw new ClassNotFoundException(className);
+    }
+
     public static Class<?> obc(String className) throws ClassNotFoundException {
         return Class.forName(BASE + "." + className);
     }

bukkit/src/main/java/com/viaversion/viaversion/bukkit/handlers/BukkitEncodeHandler.java

@@ -37,7 +37,7 @@ import java.util.List;
 
 @ChannelHandler.Sharable
 public final class BukkitEncodeHandler extends ViaEncodeHandler {
-    private boolean handledCompression = BukkitChannelInitializer.COMPRESSION_ENABLED_EVENT != null;
+    private boolean handledCompression = BukkitChannelInitializer.COMPRESSION_ENABLED_EVENT != null || Boolean.getBoolean("com.viaversion.disableLegacyCompressionReorder");
 
     public BukkitEncodeHandler(final UserConnection connection) {
         super(connection);
@@ -56,7 +56,7 @@ public final class BukkitEncodeHandler extends ViaEncodeHandler {
 
         final ByteBuf transformedBuf = ByteBufUtil.copy(ctx.alloc(), bytebuf);
         try {
-            final boolean needsCompression = !handledCompression && handleCompressionOrder(ctx, transformedBuf);
+            final boolean needsCompression = !handledCompression && connection.getProtocolInfo().compressionEnabled() && handleCompressionOrder(ctx, transformedBuf);
             connection.transformClientbound(transformedBuf, CancelEncoderException::generate);
             if (needsCompression) {
                 recompress(ctx, transformedBuf);

bukkit/src/main/java/com/viaversion/viaversion/bukkit/platform/BukkitViaInjector.java

@@ -105,7 +105,8 @@ public class BukkitViaInjector extends LegacyViaInjector {
         // Grab the ping class and find the field to access it
         Class<?> pingClazz = NMSUtil.nms(
             "ServerPing",
-            "net.minecraft.network.protocol.status.ServerPing"
+            "net.minecraft.network.protocol.status.ServerPing",
+            "net.minecraft.network.protocol.status.ServerStatus"
         );
         Object ping = null;
         for (Field field : serverClazz.getDeclaredFields()) {
@@ -120,7 +121,8 @@ public class BukkitViaInjector extends LegacyViaInjector {
         // Now get the ServerData inside ServerPing
         Class<?> serverDataClass = NMSUtil.nms(
             "ServerPing$ServerData",
-            "net.minecraft.network.protocol.status.ServerPing$ServerData"
+            "net.minecraft.network.protocol.status.ServerPing$ServerData",
+            "net.minecraft.network.protocol.status.ServerStatus$Version"
         );
         Object serverData = null;
         for (Field field : pingClazz.getDeclaredFields()) {
@@ -155,7 +157,8 @@ public class BukkitViaInjector extends LegacyViaInjector {
         );
         Class<?> connectionClass = NMSUtil.nms(
             "ServerConnection",
-            "net.minecraft.server.network.ServerConnection"
+            "net.minecraft.server.network.ServerConnection",
+            "net.minecraft.server.network.ServerConnectionListener"
         );
 
         Object server = ReflectionUtil.invokeStatic(serverClass, "getServer");

bukkit/src/main/java/com/viaversion/viaversion/classgenerator/generated/HandlerSupplier.java

@@ -1,44 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2026 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.classgenerator.generated;
-
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.bukkit.handlers.BukkitDecodeHandler;
-import com.viaversion.viaversion.bukkit.handlers.BukkitEncodeHandler;
-import io.netty.buffer.ByteBuf;
-import io.netty.handler.codec.MessageToMessageDecoder;
-import io.netty.handler.codec.MessageToMessageEncoder;
-
-public interface HandlerSupplier {
-
-    MessageToMessageEncoder<ByteBuf> newEncodeHandler(UserConnection connection);
-
-    MessageToMessageDecoder<ByteBuf> newDecodeHandler(UserConnection connection);
-
-    final class DefaultHandlerSupplier implements HandlerSupplier {
-        @Override
-        public MessageToMessageEncoder<ByteBuf> newEncodeHandler(final UserConnection connection) {
-            return new BukkitEncodeHandler(connection);
-        }
-
-        @Override
-        public MessageToMessageDecoder<ByteBuf> newDecodeHandler(final UserConnection connection) {
-            return new BukkitDecodeHandler(connection);
-        }
-    }
-}

common/src/main/java/com/viaversion/viaversion/api/protocol/AbstractProtocol.java

@@ -2,23 +2,18 @@
  * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
  * Copyright (C) 2016-2026 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:
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
  *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
  *
- * 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.
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 package com.viaversion.viaversion.api.protocol;
 
@@ -39,10 +34,15 @@ import com.viaversion.viaversion.api.protocol.packet.provider.PacketTypeMap;
 import com.viaversion.viaversion.api.protocol.packet.provider.PacketTypesProvider;
 import com.viaversion.viaversion.api.protocol.packet.provider.SimplePacketTypesProvider;
 import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
+import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import com.viaversion.viaversion.api.rewriter.MappingDataListener;
 import com.viaversion.viaversion.api.rewriter.Rewriter;
 import com.viaversion.viaversion.exception.CancelException;
 import com.viaversion.viaversion.exception.InformativeException;
+import com.viaversion.viaversion.protocol.shared_registration.SharedRegistrations;
+import com.viaversion.viaversion.rewriter.RecipeDisplayRewriter;
+import com.viaversion.viaversion.rewriter.TagRewriter;
+import com.viaversion.viaversion.rewriter.text.ComponentRewriterBase;
 import com.viaversion.viaversion.util.ProtocolLogger;
 import com.viaversion.viaversion.util.ProtocolUtil;
 import java.util.HashMap;
@@ -74,6 +74,8 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
     private final Map<Class<?>, Object> storedObjects = new HashMap<>();
     private boolean initialized;
     private ProtocolLogger logger;
+    private ProtocolVersion serverVersion;
+    private ProtocolVersion clientVersion;
 
     @Deprecated
     protected AbstractProtocol() {
@@ -104,6 +106,11 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         if (logger == null) {
             logger = createLogger();
         }
+
+        // Apply shared registrations based on protocol version range
+        // Run before registerPackets, so implementations have to call append intentionally
+        applySharedRegistrations();
+
         registerPackets();
         registerConfigurationChangeHandlers();
 
@@ -128,6 +135,13 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         }
     }
 
+    /**
+     * Applies shared registrations. Can be overridden to remove or add registrations.
+     */
+    protected void applySharedRegistrations() {
+        SharedRegistrations.defaultRegistrations().applyMatching(this);
+    }
+
     protected ProtocolLogger createLogger() {
         return new ProtocolLogger(getClass());
     }
@@ -177,6 +191,20 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         }
     }
 
+    @Override
+    public void replaceClientbound(final CU type, @Nullable final PacketHandler handler) {
+        final PacketMapping mapping = clientboundMappings.mappedPacket(type.state(), type.getId());
+        Preconditions.checkNotNull(mapping, "Packet %s has no handler to replace", type);
+        mapping.setHandler(handler);
+    }
+
+    @Override
+    public void replaceServerbound(final SU type, @Nullable final PacketHandler handler) {
+        final PacketMapping mapping = serverboundMappings.mappedPacket(type.state(), type.getId());
+        Preconditions.checkNotNull(mapping, "Packet %s has no handler to replace", type);
+        mapping.setHandler(handler);
+    }
+
     private <U extends PacketType, M extends PacketType> void registerPacketIdChanges(
         Map<State, PacketTypeMap<U>> unmappedPacketTypes,
         Map<State, PacketTypeMap<M>> mappedPacketTypes,
@@ -214,6 +242,7 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
     @Override
     public final void loadMappingData() {
         getMappingData().load();
+        initialize();
         onMappingDataLoaded();
     }
 
@@ -289,6 +318,46 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         return packetTypesProvider.unmappedClientboundType(State.CONFIGURATION, "FINISH_CONFIGURATION");
     }
 
+    /**
+     * Returns the server protocol version for this protocol,
+     * or null if not set (e.g. for base protocols).
+     *
+     * @return the server protocol version
+     */
+    public @Nullable ProtocolVersion getServerVersion() {
+        return serverVersion;
+    }
+
+    /**
+     * Sets the server protocol version for this protocol.
+     * Called by the protocol manager before {@link #initialize()}.
+     *
+     * @param serverVersion the server protocol version
+     */
+    public void setServerVersion(final ProtocolVersion serverVersion) {
+        this.serverVersion = serverVersion;
+    }
+
+    /**
+     * Returns the client protocol version for this protocol,
+     * or null if not set (e.g. for base protocols).
+     *
+     * @return the client protocol version for this protocol
+     */
+    public @Nullable ProtocolVersion getClientVersion() {
+        return clientVersion;
+    }
+
+    /**
+     * Sets the client protocol version for this protocol.
+     * Called by the protocol manager before {@link #initialize()}.
+     *
+     * @param clientVersion the client protocol version for this protocol
+     */
+    public void setClientVersion(final ProtocolVersion clientVersion) {
+        this.clientVersion = clientVersion;
+    }
+
     // ---------------------------------------------------------------------------------
 
     @Override
@@ -297,7 +366,7 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         PacketMapping packetMapping = PacketMapping.of(mappedPacketId, handler);
         if (!override && serverboundMappings.hasMapping(state, unmappedPacketId)) {
             Via.getPlatform().getLogger().log(Level.WARNING, unmappedPacketId + " already registered!" +
-                " If this override is intentional, set override to true. Stacktrace: ", new Exception());
+                " If this override is intentional, use replaceServerbound instead. Stacktrace: ", new Exception());
         }
         serverboundMappings.addMapping(state, unmappedPacketId, packetMapping);
     }
@@ -313,7 +382,7 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         PacketMapping packetMapping = PacketMapping.of(mappedPacketId, handler);
         if (!override && clientboundMappings.hasMapping(state, unmappedPacketId)) {
             Via.getPlatform().getLogger().log(Level.WARNING, unmappedPacketId + " already registered!" +
-                " If override is intentional, set override to true. Stacktrace: ", new Exception());
+                " If override is intentional, use replaceClientbound instead. Stacktrace: ", new Exception());
         }
         clientboundMappings.addMapping(state, unmappedPacketId, packetMapping);
     }
@@ -373,8 +442,8 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
 
         PacketMapping packetMapping = PacketMapping.of(mappedPacketType, handler);
         if (!override && packetMappings.hasMapping(packetType)) {
-            getLogger().log(Level.WARNING, packetType + " already registered!" +
-                " If override is intentional, set override to true. Stacktrace: ", new Exception());
+            throw new IllegalArgumentException("Packet type " + packetType + " already registered! If override is intentional, use "
+                + (packetType.direction() == Direction.SERVERBOUND ? "replaceServerbound" : "replaceClientbound") + " instead.");
         }
         packetMappings.addMapping(packetType, packetMapping);
     }
@@ -443,6 +512,39 @@ public abstract class AbstractProtocol<CU extends ClientboundPacketType, CM exte
         return logger;
     }
 
+    @Override
+    public @Nullable TagRewriter<CU> getTagRewriter() {
+        return null;
+    }
+
+    @Override
+    public @Nullable ComponentRewriterBase<CU> getComponentRewriter() {
+        return null;
+    }
+
+    @Override
+    public com.viaversion.viaversion.rewriter.@Nullable ParticleRewriter<CU> getParticleRewriter() {
+        return null;
+    }
+
+    @Override
+    public com.viaversion.viaversion.rewriter.@Nullable EntityRewriter<CU, ?> getEntityRewriter() {
+        return null;
+    }
+
+    @Override
+    public com.viaversion.viaversion.rewriter.@Nullable ItemRewriter<CU, SU, ?> getItemRewriter() {
+        return null;
+    }
+
+    public com.viaversion.viaversion.rewriter.@Nullable BlockRewriter<CU> getBlockRewriter() {
+        return null;
+    }
+
+    public @Nullable RecipeDisplayRewriter<CU> getRecipeRewriter() {
+        return null;
+    }
+
     private void printRemapError(Direction direction, State state, int unmappedPacketId, int mappedPacketId, InformativeException e) {
         // Don't print errors during handshake/login/status
         if (state != State.PLAY && direction == Direction.SERVERBOUND && !Via.getManager().debugHandler().enabled()) {

common/src/main/java/com/viaversion/viaversion/codec/CodecRegistryContext.java

@@ -30,7 +30,7 @@ public record CodecRegistryContext(Protocol<?, ?, ?, ?> protocol, RegistryAccess
 
     // Generally from hardcoded, but highly variable client data
     private static final Set<StructuredDataKey<?>> NOT_IMPLEMENTED = new ReferenceOpenHashSet<>(List.of(
-        StructuredDataKey.DAMAGE_TYPE
+        StructuredDataKey.DAMAGE_TYPE1_21_11
     ));
 
     public CodecRegistryContext(final Protocol<?, ?, ?, ?> protocol, final RegistryAccess registryAccess, final boolean mapped) {

common/src/main/java/com/viaversion/viaversion/codec/hash/HashBuilder.java

@@ -22,9 +22,11 @@ import java.util.Arrays;
 public final class HashBuilder {
 
     private static final byte[] EMPTY_BYTES = new byte[0];
+    private static final int MAX_RETAINED_CAPACITY = 4096;
     private final HashFunction hashFunction;
     private byte[] bytes = EMPTY_BYTES;
     private int index;
+    private boolean direct;
 
     public HashBuilder(final HashFunction hashFunction) {
         this.hashFunction = hashFunction;
@@ -43,11 +45,17 @@ public final class HashBuilder {
         return this;
     }
 
+    /**
+     * Writes the given bytes directly, avoiding a copy if currently empty.
+     *
+     * @param bytes the bytes to write directly
+     */
     public void writeBytesDirect(final byte[] bytes) {
         if (this.bytes.length == 0) {
             // Set bytes directly if still empty
             this.bytes = bytes;
             this.index = bytes.length;
+            this.direct = true;
         } else {
             writeBytes(bytes);
         }
@@ -75,9 +83,11 @@ public final class HashBuilder {
 
     public HashBuilder writeString(final CharSequence sequence) {
         final int length = sequence.length();
-        this.ensureSize(length);
+        this.ensureSize(length * 2);
         for (int i = 0; i < length; i++) {
-            this.writeChar(sequence.charAt(i));
+            final char c = sequence.charAt(i);
+            this.bytes[this.index++] = (byte) c;
+            this.bytes[this.index++] = (byte) (c >> 8);
         }
         return this;
     }
@@ -130,9 +140,11 @@ public final class HashBuilder {
 
     private void ensureSize(final int bytes) {
         final int length = this.bytes.length;
-        if (this.index + bytes > length) {
-            final int newLength = Math.max(length * 2, this.index + bytes);
+        final int required = this.index + bytes;
+        if (required > length) {
+            final int newLength = Math.max(length * 2, required);
             this.bytes = Arrays.copyOf(this.bytes, newLength);
+            this.direct = false;
         }
     }
 
@@ -142,7 +154,11 @@ public final class HashBuilder {
 
     public void reset() {
         this.index = 0;
-        this.bytes = EMPTY_BYTES;
+        // Discard the buffer if it was direct (externally owned) or exceeds max retained capacity
+        if (this.direct || this.bytes.length > MAX_RETAINED_CAPACITY) {
+            this.bytes = EMPTY_BYTES;
+            this.direct = false;
+        }
     }
 
     public HashFunction function() {

common/src/main/java/com/viaversion/viaversion/commands/defaultsubs/DebugSubCmd.java

@@ -37,6 +37,11 @@ public class DebugSubCmd implements ViaSubCommand {
         return "Toggle various debug modes.";
     }
 
+    @Override
+    public String usage() {
+        return "debug [clear|pre|post], or debug <add|remove> <packet>";
+    }
+
     @Override
     public boolean execute(ViaCommandSender sender, String[] args) {
         final DebugHandler debug = Via.getManager().debugHandler();
@@ -49,11 +54,11 @@ public class DebugSubCmd implements ViaSubCommand {
                 debug.clearPacketTypesToLog();
                 sendMessage(sender, "&6Cleared packet types to log");
                 return true;
-            } else if (args[0].equalsIgnoreCase("logpretransform")) {
+            } else if (args[0].equalsIgnoreCase("pre")) {
                 debug.setLogPrePacketTransform(!debug.logPrePacketTransform());
                 sendMessage(sender, "&6Pre transform packet logging is now %s", (debug.logPrePacketTransform() ? "&aenabled" : "&cdisabled"));
                 return true;
-            } else if (args[0].equalsIgnoreCase("logposttransform")) {
+            } else if (args[0].equalsIgnoreCase("post")) {
                 debug.setLogPostPacketTransform(!debug.logPostPacketTransform());
                 sendMessage(sender, "&6Post transform packet logging is now %s", (debug.logPostPacketTransform() ? "&aenabled" : "&cdisabled"));
                 return true;
@@ -75,7 +80,7 @@ public class DebugSubCmd implements ViaSubCommand {
     @Override
     public List<String> onTabComplete(final ViaCommandSender sender, final String[] args) {
         if (args.length == 1) {
-            return Arrays.asList("clear", "logposttransform", "add", "remove");
+            return Arrays.asList("clear", "pre", "post", "add", "remove");
         }
         return Collections.emptyList();
     }

common/src/main/java/com/viaversion/viaversion/commands/defaultsubs/DisplayLeaksSubCmd.java

@@ -37,7 +37,7 @@ public class DisplayLeaksSubCmd implements ViaSubCommand {
 
     @Override
     public String usage() {
-        return "displayleaks <level>";
+        return "displayleaks [level]";
     }
 
     @Override

common/src/main/java/com/viaversion/viaversion/connection/ConnectionDetails.java

@@ -64,24 +64,21 @@ public final class ConnectionDetails {
             return;
         }
 
-        final ProtocolInfo protocolInfo = connection.getProtocolInfo();
-        final ProtocolVersion nativeVersion = protocolInfo.protocolVersion();
-        final ProtocolVersion serverVersion = protocolInfo.serverProtocolVersion();
-        if (serverVersion.equals(nativeVersion)) {
-            // No need to send details if the native version is the same as the server version
-            return;
-        }
+        final JsonObject payload = new JsonObject();
+        payload.addProperty("specVersion", VERSION);
 
         final String platformName = Via.getPlatform().getPlatformName();
         final String platformVersion = Via.getPlatform().getPlatformVersion();
 
-        final JsonObject payload = new JsonObject();
-        payload.addProperty("specVersion", VERSION);
+        final ProtocolInfo protocolInfo = connection.getProtocolInfo();
+        final ProtocolVersion clientVersion = protocolInfo.protocolVersion();
 
         payload.addProperty("platformName", platformName);
         payload.addProperty("platformVersion", platformVersion);
-        payload.addProperty("version", nativeVersion.getOriginalVersion());
-        payload.addProperty("versionName", nativeVersion.getName());
+        payload.addProperty("version", clientVersion.getOriginalVersion());
+        payload.addProperty("versionName", clientVersion.getName());
+        payload.addProperty("versionType", clientVersion.getVersionType().name());
+        Via.getPlatform().modifyPlayerDetails(connection, payload);
 
         Via.getPlatform().sendCustomPayload(connection, channel, payload.toString().getBytes(StandardCharsets.UTF_8));
     }
@@ -98,13 +95,15 @@ public final class ConnectionDetails {
             return;
         }
 
-        final ProtocolInfo protocolInfo = connection.getProtocolInfo();
-        final ProtocolVersion serverVersion = protocolInfo.serverProtocolVersion();
         final JsonObject payload = new JsonObject();
         payload.addProperty("specVersion", VERSION);
 
+        final ProtocolInfo protocolInfo = connection.getProtocolInfo();
+        final ProtocolVersion serverVersion = protocolInfo.serverProtocolVersion();
         payload.addProperty("version", serverVersion.getOriginalVersion());
         payload.addProperty("versionName", serverVersion.getName());
+        payload.addProperty("versionType", serverVersion.getVersionType().name());
+        Via.getPlatform().modifyServerDetails(connection, payload);
 
         Via.getPlatform().sendCustomPayloadToClient(connection, channel, payload.toString().getBytes(StandardCharsets.UTF_8));
     }

common/src/main/java/com/viaversion/viaversion/connection/ProtocolInfoImpl.java

@@ -32,6 +32,7 @@ public class ProtocolInfoImpl implements ProtocolInfo {
     private String username;
     private UUID uuid;
     private ProtocolPipeline pipeline;
+    private boolean compressionEnabled;
 
     @Override
     public State getClientState() {
@@ -99,6 +100,16 @@ public class ProtocolInfoImpl implements ProtocolInfo {
         this.uuid = uuid;
     }
 
+    @Override
+    public boolean compressionEnabled() {
+        return compressionEnabled;
+    }
+
+    @Override
+    public void setCompressionEnabled(final boolean compressionEnabled) {
+        this.compressionEnabled = compressionEnabled;
+    }
+
     @Override
     public ProtocolPipeline getPipeline() {
         return pipeline;

common/src/main/java/com/viaversion/viaversion/data/entity/EntityTrackerBase.java

@@ -215,7 +215,7 @@ public class EntityTrackerBase implements EntityTracker, ClientEntityIdChangeLis
 
     @Override
     public @Nullable DimensionData dimensionData(int dimensionId) {
-        return dimensions.values().stream().filter(data -> data.id() == dimensionId).findFirst().orElse(null); // TODO Store as array as well
+        return dimensions.values().stream().filter(data -> data.id() == dimensionId).findFirst().orElse(null);
     }
 
     @Override

common/src/main/java/com/viaversion/viaversion/data/item/ItemHasherBase.java

@@ -116,6 +116,8 @@ public class ItemHasherBase implements ItemHasher {
                 entry.setValue(clientProvidedHash);
             }
         }
+
+        originalItem.setAmount(clientItem.amount());
         return originalItem;
     }
 

common/src/main/java/com/viaversion/viaversion/platform/UserConnectionViaVersionPlatform.java

@@ -49,6 +49,11 @@ public abstract class UserConnectionViaVersionPlatform implements ViaPlatform<Us
     @Override
     public abstract Logger createLogger(String name);
 
+    @Override
+    public boolean isProxy() {
+        return true;
+    }
+
     @Override
     public Logger getLogger() {
         return logger;

common/src/main/java/com/viaversion/viaversion/platform/ViaChannelInitializer.java

@@ -17,10 +17,13 @@
  */
 package com.viaversion.viaversion.platform;
 
+import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.platform.ViaInjector;
 import com.viaversion.viaversion.connection.UserConnectionImpl;
 import com.viaversion.viaversion.protocol.ProtocolPipelineImpl;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import java.lang.reflect.Method;
@@ -59,6 +62,30 @@ public abstract class ViaChannelInitializer extends ChannelInitializer<Channel>
         return connection;
     }
 
+    /**
+     * Reorders the ViaVersion handlers in the pipeline to be after the specified handlers. This is needed in platforms
+     * where enabling the compression breaks the order of Via handlers to be: encoder -> compressor -> via encoder.
+     *
+     * @param pipeline   The channel pipeline
+     * @param compress   The name of the compress handler where Via's encoder was initially placed after
+     * @param decompress The name of the decompress handler where Via's decoder was initially placed after
+     */
+    public static void reorderPipeline(final ChannelPipeline pipeline, final String compress, final String decompress) {
+        final ViaInjector injector = Via.getManager().getInjector();
+        final int decompressIndex = pipeline.names().indexOf(decompress);
+        if (decompressIndex == -1) {
+            return;
+        }
+
+        if (decompressIndex > pipeline.names().indexOf(injector.getDecoderName())) {
+            final ChannelHandler encoderHandler = pipeline.remove(injector.getEncoderName());
+            final ChannelHandler decoderHandler = pipeline.remove(injector.getDecoderName());
+
+            pipeline.addAfter(compress, injector.getEncoderName(), encoderHandler);
+            pipeline.addAfter(decompress, injector.getDecoderName(), decoderHandler);
+        }
+    }
+
     protected abstract void injectPipeline(ChannelPipeline pipeline, UserConnection connection);
 
     @Override

common/src/main/java/com/viaversion/viaversion/protocol/AbstractSimpleProtocol.java

@@ -0,0 +1,34 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2026 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viaversion.protocol;
+
+import com.viaversion.viaversion.api.protocol.AbstractProtocol;
+import com.viaversion.viaversion.api.protocol.SimpleProtocol;
+
+/**
+ * A simple protocol which does not have any packet types.
+ * <p>
+ * {@link AbstractProtocol} should be preferred over this class in most cases.
+ */
+public abstract class AbstractSimpleProtocol extends AbstractProtocol<SimpleProtocol.DummyPacketTypes, SimpleProtocol.DummyPacketTypes,
+    SimpleProtocol.DummyPacketTypes, SimpleProtocol.DummyPacketTypes> implements SimpleProtocol {
+
+    protected AbstractSimpleProtocol() {
+        super(null, null, null, null);
+    }
+}

common/src/main/java/com/viaversion/viaversion/protocol/ProtocolManagerImpl.java

@@ -23,6 +23,7 @@ import com.google.common.collect.Range;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.data.MappingDataLoader;
+import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.ProtocolManager;
 import com.viaversion.viaversion.api.protocol.ProtocolPathEntry;
@@ -38,6 +39,7 @@ import com.viaversion.viaversion.api.protocol.version.ServerProtocolVersion;
 import com.viaversion.viaversion.api.protocol.version.VersionType;
 import com.viaversion.viaversion.protocol.packet.PacketWrapperImpl;
 import com.viaversion.viaversion.protocol.packet.VersionedPacketTransformerImpl;
+import com.viaversion.viaversion.protocol.shared_registration.def.DefaultRegistrations;
 import com.viaversion.viaversion.protocols.base.InitialBaseProtocol;
 import com.viaversion.viaversion.protocols.base.v1_16.ClientboundBaseProtocol1_16;
 import com.viaversion.viaversion.protocols.base.v1_7.ClientboundBaseProtocol1_7;
@@ -76,6 +78,7 @@ import com.viaversion.viaversion.protocols.v1_20_2to1_20_3.Protocol1_20_2To1_20_
 import com.viaversion.viaversion.protocols.v1_20_3to1_20_5.Protocol1_20_3To1_20_5;
 import com.viaversion.viaversion.protocols.v1_20_5to1_21.Protocol1_20_5To1_21;
 import com.viaversion.viaversion.protocols.v1_20to1_20_2.Protocol1_20To1_20_2;
+import com.viaversion.viaversion.protocols.v1_21_11to26_1.Protocol1_21_11To26_1;
 import com.viaversion.viaversion.protocols.v1_21_2to1_21_4.Protocol1_21_2To1_21_4;
 import com.viaversion.viaversion.protocols.v1_21_4to1_21_5.Protocol1_21_4To1_21_5;
 import com.viaversion.viaversion.protocols.v1_21_5to1_21_6.Protocol1_21_5To1_21_6;
@@ -94,6 +97,7 @@ import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectSortedMap;
+import it.unimi.dsi.fastutil.objects.Reference2ObjectOpenHashMap;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -112,9 +116,7 @@ import java.util.concurrent.ForkJoinWorkerThread;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.function.Function;
 import java.util.logging.Level;
-import it.unimi.dsi.fastutil.objects.Reference2ObjectOpenHashMap;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class ProtocolManagerImpl implements ProtocolManager {
@@ -145,6 +147,8 @@ public class ProtocolManagerImpl implements ProtocolManager {
             worker.setName("Via-Mappingloader-" + threadIndex.incrementAndGet());
             return worker;
         }, ForkJoinWorkerThread.getDefaultUncaughtExceptionHandler(), true);
+
+        DefaultRegistrations.apply();
     }
 
     public void registerProtocols() {
@@ -213,6 +217,8 @@ public class ProtocolManagerImpl implements ProtocolManager {
         registerProtocol(new Protocol1_21_6To1_21_7(), ProtocolVersion.v1_21_7, ProtocolVersion.v1_21_6);
         registerProtocol(new Protocol1_21_7To1_21_9(), ProtocolVersion.v1_21_9, ProtocolVersion.v1_21_7);
         registerProtocol(new Protocol1_21_9To1_21_11(), ProtocolVersion.v1_21_11, ProtocolVersion.v1_21_9);
+
+        registerProtocol(new Protocol1_21_11To26_1(), ProtocolVersion.v26_1, ProtocolVersion.v1_21_11);
     }
 
     @Override
@@ -222,8 +228,11 @@ public class ProtocolManagerImpl implements ProtocolManager {
 
     @Override
     public void registerProtocol(Protocol protocol, List<ProtocolVersion> supportedClientVersion, ProtocolVersion serverVersion) {
-        // Register the protocol's handlers
-        protocol.initialize();
+        // Set the server version on AbstractProtocol instances before initialization
+        if (protocol instanceof AbstractProtocol<?, ?, ?, ?> abstractProtocol) {
+            abstractProtocol.setServerVersion(serverVersion);
+            abstractProtocol.setClientVersion(supportedClientVersion.stream().max(ProtocolVersion::compareTo).orElseThrow());
+        }
 
         // Clear cache as this may make new routes.
         if (!pathCache.isEmpty()) {
@@ -245,14 +254,22 @@ public class ProtocolManagerImpl implements ProtocolManager {
             refreshVersions();
         }
 
-        if (protocol.hasMappingDataToLoad()) {
-            if (mappingLoaderExecutor != null) {
-                // Submit mapping data loading
-                addMappingLoaderFuture(protocol.getClass(), protocol::loadMappingData);
+        // Load mapping data and register the protocol's handlers
+        if (!protocol.hasMappingDataToLoad()) {
+            protocol.initialize();
+            return;
+        }
+
+        // Submit mapping data loading
+        if (mappingLoaderExecutor != null) {
+            if (protocol.dependsOn() != null) {
+                addMappingLoaderFuture(protocol.getClass(), protocol.dependsOn(), protocol::loadMappingData);
             } else {
-                // Late protocol adding - just do it on the current thread
-                protocol.loadMappingData();
+                addMappingLoaderFuture(protocol.getClass(), protocol::loadMappingData);
             }
+        } else {
+            // Late protocol adding - just do it on the current thread
+            protocol.loadMappingData();
         }
     }
 
@@ -481,7 +498,7 @@ public class ProtocolManagerImpl implements ProtocolManager {
     }
 
     @Override
-    public boolean checkForMappingCompletion() {
+    public boolean checkForMappingCompletion(final boolean propagateErrors) {
         mappingLoaderLock.readLock().lock();
         try {
             if (mappingsLoaded) {
@@ -493,6 +510,9 @@ public class ProtocolManagerImpl implements ProtocolManager {
                 if (!future.isDone()) {
                     return false;
                 }
+                if (propagateErrors) {
+                    future.join();
+                }
             }
 
             shutdownLoaderExecutor();
@@ -504,7 +524,8 @@ public class ProtocolManagerImpl implements ProtocolManager {
 
     @Override
     public void addMappingLoaderFuture(Class<? extends Protocol> protocolClass, Runnable runnable) {
-        CompletableFuture<Void> future = CompletableFuture.runAsync(runnable, mappingLoaderExecutor).exceptionally(mappingLoaderThrowable(protocolClass));
+        CompletableFuture<Void> future = CompletableFuture.runAsync(runnable, mappingLoaderExecutor)
+            .whenComplete(($, t) -> logIfErrored(protocolClass, t));
 
         mappingLoaderLock.writeLock().lock();
         try {
@@ -516,8 +537,8 @@ public class ProtocolManagerImpl implements ProtocolManager {
 
     @Override
     public void addMappingLoaderFuture(Class<? extends Protocol> protocolClass, Class<? extends Protocol> dependsOn, Runnable runnable) {
-        CompletableFuture<Void> future = getMappingLoaderFuture(dependsOn)
-            .whenCompleteAsync((v, throwable) -> runnable.run(), mappingLoaderExecutor).exceptionally(mappingLoaderThrowable(protocolClass));
+        CompletableFuture<Void> future = getMappingLoaderFuture(dependsOn).thenRunAsync(runnable, mappingLoaderExecutor)
+            .whenComplete(($, t) -> logIfErrored(protocolClass, t));
 
         mappingLoaderLock.writeLock().lock();
         try {
@@ -568,10 +589,9 @@ public class ProtocolManagerImpl implements ProtocolManager {
         MappingDataLoader.INSTANCE.clearCache();
     }
 
-    private Function<Throwable, Void> mappingLoaderThrowable(Class<? extends Protocol> protocolClass) {
-        return throwable -> {
-            Via.getPlatform().getLogger().log(Level.SEVERE, "Error during mapping loading of " + protocolClass.getSimpleName(), throwable);
-            return null;
-        };
+    private void logIfErrored(final Class<? extends Protocol> protocolClass, @Nullable final Throwable throwable) {
+        if (throwable != null) {
+            Via.getPlatform().getLogger().log(Level.SEVERE, "Error during loading of " + protocolClass.getSimpleName(), throwable);
+        }
     }
 }

common/src/main/java/com/viaversion/viaversion/protocol/packet/PacketWrapperImpl.java

@@ -478,6 +478,19 @@ public class PacketWrapperImpl implements PacketWrapper {
         this.packetValues.clear();
     }
 
+    @Override
+    public void rewindReader(final int values) {
+        if (allActionsRead) {
+            return;
+        }
+
+        final int size = packetValues.size();
+        Preconditions.checkArgument(values <= size, "Tried resetting more values than there are readable values");
+        for (int i = size - 1; i >= size - values; i--) {
+            this.readableObjects.addFirst(this.packetValues.remove(i));
+        }
+    }
+
     @Override
     public void sendToServerRaw() throws InformativeException {
         sendToServerRaw(true);
@@ -584,6 +597,17 @@ public class PacketWrapperImpl implements PacketWrapper {
         this.allActionsRead = allActionsRead;
     }
 
+    @Override
+    public void consumeReadsOnly(final Runnable runnable) {
+        final boolean previous = this.allActionsRead;
+        this.allActionsRead = true;
+        try {
+            runnable.run();
+        } finally {
+            this.allActionsRead = previous;
+        }
+    }
+
     @Override
     public String toString() {
         return "PacketWrapper{" +