ViaRewind 4.2.0

Signed-off-by: Florian Reuth <git@florianreuth.de>

.github/dependabot.yml

@@ -6,9 +6,17 @@ updates:
     directory: "/"
     schedule:
       interval: "monthly"
+    groups:
+      all-dependencies:
+        patterns:
+          - "*"
   - package-ecosystem: "github-actions"
     cooldown:
       default-days: 7
     directory: "/"
     schedule:
-      interval: "monthly"
+      interval: "monthly"
+    groups:
+      all-dependencies:
+        patterns:
+          - "*"

.github/workflows/build.yml

@@ -2,29 +2,31 @@ name: Build
 on: [pull_request, push, workflow_dispatch]
 permissions:
   contents: read
-
 jobs:
   build:
-    # Only run on PRs if the source branch is on a different repo. We do not need to run everything twice.
-    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
+    timeout-minutes: 30
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # 6.0.2
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@50e97c2cd7a37755bbfafc9c5b7cafaece252f6e # 6.1.0
-      - name: Set up JDK 17
-        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # 5.2.0
+        uses: gradle/actions/setup-gradle@9c971963bec38e04b3d30dcc455b5382be2fdbfb # v6.3.0
+        with:
+          cache-disabled: true
+          cache-provider: basic
+      - name: Set up Java
+        uses: actions/setup-java@dd06d9cba3e5552c54d9f8ea23572deb30010f7c # v6.0.0
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 25
           check-latest: true
       - name: Build with Gradle
-        run: ./gradlew build
+        run: ./gradlew build --stacktrace
       - name: Upload Artifacts to GitHub
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # 7.0.1
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: Artifacts
           path: build/libs/
+          if-no-files-found: error

.github/workflows/publish.yml

@@ -12,22 +12,26 @@ permissions:
 jobs:
   publish:
     if: github.repository_owner == 'ViaVersion'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
+    timeout-minutes: 30
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # 6.0.2
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@50e97c2cd7a37755bbfafc9c5b7cafaece252f6e # 6.1.0
-      - name: Set up JDK 17
-        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # 5.2.0
+        uses: gradle/actions/setup-gradle@9c971963bec38e04b3d30dcc455b5382be2fdbfb # v6.3.0
+        with:
+          cache-disabled: true
+          cache-provider: basic
+      - name: Set up Java
+        uses: actions/setup-java@dd06d9cba3e5552c54d9f8ea23572deb30010f7c # v6.0.0
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 25
           check-latest: true
       - name: Build with Gradle
-        run: ./gradlew build
+        run: ./gradlew build --stacktrace
       - name: Publish to Hangar
         env:
           HANGAR_TOKEN: ${{ secrets.HANGAR_TOKEN }}

build.gradle.kts

@@ -1,10 +1,17 @@
-import de.florianreuth.baseproject.*
+import de.florianreuth.baseproject.core.configureEmbeddedDependencies
+import de.florianreuth.baseproject.integration.branchName
+import de.florianreuth.baseproject.integration.latestCommitHash
+import de.florianreuth.baseproject.integration.latestCommitMessage
+import de.florianreuth.baseproject.setupProject
+import de.florianreuth.baseproject.setupViaPublishing
+import net.raphimc.classtokenreplacer.extension.ClassTokenReplacerExtension
 
 plugins {
     `java-library`
     id("io.papermc.hangar-publish-plugin")
     id("com.modrinth.minotaur")
     id("de.florianreuth.baseproject")
+    id("net.raphimc.class-token-replacer") apply false
 }
 
 allprojects {
@@ -13,7 +20,6 @@ allprojects {
     setupViaPublishing()
 
     repositories {
-        mavenCentral()
         maven("https://repo.viaversion.com")
         maven("https://repo.papermc.io/repository/maven-public")
         maven("https://maven.fabricmc.net")
@@ -21,11 +27,22 @@ allprojects {
 
 }
 
+val commitHash = latestCommitHash()
+
 subprojects {
 
+    apply(plugin = "net.raphimc.class-token-replacer")
+
     dependencies {
-        compileOnly("com.viaversion:viaversion:5.7.2")
-        compileOnly("com.viaversion:viabackwards:5.7.2")
+        compileOnly("com.viaversion:viaversion:5.12.0")
+        compileOnly("com.viaversion:viabackwards:5.12.0")
+    }
+
+    extensions.getByType<SourceSetContainer>().configureEach {
+        extensions.getByType(ClassTokenReplacerExtension::class.java).apply {
+            property("\${version}", project.version)
+            property("\${impl_version}", "git-ViaRewind-${project.version}:${commitHash}")
+        }
     }
 
     tasks {
@@ -40,11 +57,7 @@ subprojects {
 
 }
 
-base {
-    archivesName.set("ViaRewind")
-}
-
-val shade = configureShadedDependencies(false) // Only shade, don't add them as dependency
+val shade = configureEmbeddedDependencies()
 
 dependencies {
     subprojects.forEach {

common/build.gradle.kts

@@ -1,9 +1,3 @@
-import de.florianreuth.baseproject.latestCommitHash
-
-plugins {
-    id("net.raphimc.class-token-replacer")
-}
-
 val viaProxy: Configuration by configurations.creating
 
 dependencies {
@@ -16,15 +10,6 @@ dependencies {
     }
 }
 
-sourceSets.configureEach {
-    classTokenReplacer {
-        replaceInPlace.set(true)
-
-        property("\${version}", project.version)
-        property("\${impl_version}", "git-ViaRewind-${project.version}:${latestCommitHash()}")
-    }
-}
-
 // Task to quickly test/debug code changes using https://github.com/ViaVersion/ViaProxy
 // For further instructions see the ViaProxy repository README
 val prepareViaProxyFiles by tasks.registering(Copy::class) {

common/src/main/java/com/viaversion/viarewind/api/compression/ThreadLocalCompressionProvider.java

@@ -0,0 +1,157 @@
+/*
+ * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
+ * Copyright (C) 2018-2026 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.viarewind.api.compression;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
+
+import java.util.zip.DataFormatException;
+import java.util.zip.Deflater;
+import java.util.zip.Inflater;
+
+/**
+ * A ThreadLocal-based compression provider that either uses Velocity's native compression
+ * or falls back to Java's built-in compression (Deflater/Inflater).
+ */
+public final class ThreadLocalCompressionProvider {
+
+    private static final boolean VELOCITY_NATIVES_AVAILABLE;
+
+    static {
+        boolean velocityAvailable = false;
+        try {
+            Class.forName("com.velocitypowered.natives.compression.VelocityCompressor");
+            velocityAvailable = true;
+        } catch (final ClassNotFoundException ignored) {
+        }
+        VELOCITY_NATIVES_AVAILABLE = velocityAvailable;
+    }
+
+    // ThreadLocal for Java's Deflater (used when Velocity natives are not available)
+    private static final ThreadLocal<Deflater> JAVA_DEFLATER = ThreadLocal.withInitial(Deflater::new);
+
+    // ThreadLocal for Java's Inflater (used when Velocity natives are not available)
+    private static final ThreadLocal<Inflater> JAVA_INFLATER = ThreadLocal.withInitial(Inflater::new);
+
+    private ThreadLocalCompressionProvider() {
+    }
+
+    /**
+     * Compresses data from the source buffer into the destination buffer.
+     *
+     * @param source      the source buffer containing uncompressed data
+     * @param destination the destination buffer to write compressed data to
+     * @throws DataFormatException if compression fails
+     */
+    public static void deflate(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
+        if (VELOCITY_NATIVES_AVAILABLE) {
+            deflateVelocity(source, destination);
+        } else {
+            deflateJava(source, destination);
+        }
+    }
+
+
+    /**
+     * Decompresses data from the source buffer into the destination buffer.
+     *
+     * @param source        the source buffer containing compressed data
+     * @param destination   the destination buffer to write decompressed data to
+     * @param expectedSize  the expected size of the decompressed data
+     * @throws DataFormatException if decompression fails
+     */
+    public static void inflate(final ByteBuf source, final ByteBuf destination, final int expectedSize) throws DataFormatException {
+        if (VELOCITY_NATIVES_AVAILABLE) {
+            inflateVelocity(source, destination, expectedSize);
+        } else {
+            inflateJava(source, destination, expectedSize);
+        }
+    }
+
+    // Java native implementation
+
+    private static void deflateJava(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
+        ByteBuf temp = source;
+        if (!source.hasArray()) {
+            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(source);
+        } else {
+            source.retain();
+        }
+        ByteBuf output = ByteBufAllocator.DEFAULT.heapBuffer();
+        try {
+            final Deflater deflater = JAVA_DEFLATER.get();
+            deflater.setInput(temp.array(), temp.arrayOffset() + temp.readerIndex(), temp.readableBytes());
+            deflater.finish();
+
+            while (!deflater.finished()) {
+                output.ensureWritable(4096);
+                output.writerIndex(output.writerIndex() + deflater.deflate(output.array(), output.arrayOffset() + output.writerIndex(), output.writableBytes()));
+            }
+            destination.writeBytes(output);
+        } finally {
+            output.release();
+            temp.release();
+            JAVA_DEFLATER.get().reset();
+        }
+    }
+
+
+    private static void inflateJava(final ByteBuf source, final ByteBuf destination, final int expectedSize) throws DataFormatException {
+        ByteBuf temp = source;
+        if (!source.hasArray()) {
+            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(source);
+        } else {
+            source.retain();
+        }
+        ByteBuf output = ByteBufAllocator.DEFAULT.heapBuffer(expectedSize, expectedSize);
+        try {
+            final Inflater inflater = JAVA_INFLATER.get();
+            inflater.setInput(temp.array(), temp.arrayOffset() + temp.readerIndex(), temp.readableBytes());
+            output.writerIndex(output.writerIndex() + inflater.inflate(output.array(), output.arrayOffset(), expectedSize));
+            destination.writeBytes(output);
+        } finally {
+            output.release();
+            temp.release();
+            JAVA_INFLATER.get().reset();
+        }
+    }
+
+    // Velocity native implementation
+    private static void deflateVelocity(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
+        VelocityHolder.deflate(source, destination);
+    }
+
+    private static void inflateVelocity(final ByteBuf source, final ByteBuf destination, final int expectedSize) throws DataFormatException {
+        VelocityHolder.inflate(source, destination, expectedSize);
+    }
+
+    private static final class VelocityHolder {
+
+        private static final ThreadLocal<com.velocitypowered.natives.compression.VelocityCompressor> COMPRESSOR =
+                ThreadLocal.withInitial(() -> com.velocitypowered.natives.util.Natives.compress.get().create(-1));
+
+        static void deflate(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
+            COMPRESSOR.get().deflate(source, destination);
+        }
+
+        static void inflate(final ByteBuf source, final ByteBuf destination, final int expectedSize) throws DataFormatException {
+            COMPRESSOR.get().inflate(source, destination, expectedSize);
+        }
+    }
+}
+

common/src/main/java/com/viaversion/viarewind/api/data/RewindMappingData.java

@@ -20,6 +20,10 @@ package com.viaversion.viarewind.api.data;
 import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.viabackwards.api.data.BackwardsMappingData;
 import com.viaversion.viarewind.ViaRewind;
+import com.viaversion.viaversion.api.data.FullMappings;
+import com.viaversion.viaversion.api.data.LegacyFullStringMappingsBase;
+import com.viaversion.viaversion.api.data.MappingDataLoader;
+import com.viaversion.viaversion.api.data.Mappings;
 import java.util.logging.Logger;
 
 public class RewindMappingData extends BackwardsMappingData {
@@ -37,4 +41,9 @@ public class RewindMappingData extends BackwardsMappingData {
     protected CompoundTag readMappingsFile(String name) {
         return RewindMappingDataLoader.INSTANCE.loadNBTFromDir(name);
     }
+
+    @Override
+    protected FullMappings createFullMappings(MappingDataLoader.IdentifiersPair identifiersPair, Mappings mappings) {
+        return new LegacyFullStringMappingsBase(identifiersPair, mappings);
+    }
 }

common/src/main/java/com/viaversion/viarewind/api/minecraft/math/RelativeMoveUtil.java

@@ -17,17 +17,13 @@
  */
 package com.viaversion.viarewind.api.minecraft.math;
 
-import com.viaversion.viarewind.protocol.v1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.EntityTracker1_9;
-import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.Vector;
 
 @Deprecated // ?????????
 public class RelativeMoveUtil {
 
-    public static Vector[] calculateRelativeMoves(UserConnection user, int entityId, int relX, int relY, int relZ) {
-        EntityTracker1_9 tracker = user.getEntityTracker(Protocol1_9To1_8.class);
-
+    public static Vector[] calculateRelativeMoves(EntityTracker1_9 tracker, int entityId, int relX, int relY, int relZ) {
         int x;
         int y;
         int z;

common/src/main/java/com/viaversion/viarewind/api/type/chunk/BulkChunkType1_7_6.java

@@ -17,11 +17,13 @@
  */
 package com.viaversion.viarewind.api.type.chunk;
 
+import com.viaversion.viarewind.api.compression.ThreadLocalCompressionProvider;
 import com.viaversion.viaversion.api.minecraft.chunks.Chunk;
 import com.viaversion.viaversion.api.type.Type;
 import io.netty.buffer.ByteBuf;
 
-import java.util.zip.Deflater;
+import java.util.zip.DataFormatException;
+
 
 public class BulkChunkType1_7_6 extends Type<Chunk[]> {
 
@@ -63,40 +65,47 @@ public class BulkChunkType1_7_6 extends Type<Chunk[]> {
             );
         }
 
-        final byte[] data = new byte[totalSize];
-        int offset = 0;
+        final ByteBuf uncompressed = buffer.alloc().buffer(totalSize);
 
-        for (int i = 0; i < chunkCount; i++) {
-            Chunk chunk = chunks[i];
-            boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
-
-            offset = ChunkType1_7_6.serialize(
-                chunk,
-                data,
-                offset,
-                addBitMasks[i],
-                anySkyLight,
-                biomes
-            );
-        }
-
-        buffer.writeShort(chunkCount);
-
-        final Deflater deflater = new Deflater();
-        byte[] compressedData;
-        int compressedSize;
         try {
-            deflater.setInput(data, 0, data.length);
-            deflater.finish();
-            compressedData = new byte[data.length];
-            compressedSize = deflater.deflate(compressedData);
-        } finally {
-            deflater.end();
-        }
+            for (int i = 0; i < chunkCount; i++) {
+                Chunk chunk = chunks[i];
+                boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
 
-        buffer.writeInt(compressedSize);
-        buffer.writeBoolean(anySkyLight);
-        buffer.writeBytes(compressedData, 0, compressedSize);
+                ChunkType1_7_6.serialize(
+                    chunk,
+                    uncompressed,
+                    addBitMasks[i],
+                    anySkyLight,
+                    biomes
+                );
+            }
+
+            buffer.writeShort(chunkCount);
+
+            // Reserve 4 bytes for the compressed size
+            final int sizeIndex = buffer.writerIndex();
+            buffer.writeInt(0); // Placeholder for compressed size
+
+            buffer.writeBoolean(anySkyLight);
+
+            // Write compressed data directly to output buffer
+            final int compressedStart = buffer.writerIndex();
+            try {
+                ThreadLocalCompressionProvider.deflate(uncompressed, buffer);
+            } catch (DataFormatException e) {
+                throw new RuntimeException("Failed to compress bulk chunk data", e);
+            }
+            final int compressedSize = buffer.writerIndex() - compressedStart;
+
+            // Go back and write the compressed size
+            final int endIndex = buffer.writerIndex();
+            buffer.writerIndex(sizeIndex);
+            buffer.writeInt(compressedSize);
+            buffer.writerIndex(endIndex);
+        } finally {
+            uncompressed.release();
+        }
 
         for (int i = 0; i < chunkCount; i++) {
             Chunk chunk = chunks[i];

common/src/main/java/com/viaversion/viarewind/api/type/chunk/ChunkType1_7_6.java

@@ -17,13 +17,15 @@
  */
 package com.viaversion.viarewind.api.type.chunk;
 
+import com.viaversion.viarewind.api.compression.ThreadLocalCompressionProvider;
 import com.viaversion.viaversion.api.minecraft.chunks.Chunk;
 import com.viaversion.viaversion.api.minecraft.chunks.ChunkSection;
 import com.viaversion.viaversion.api.minecraft.chunks.DataPalette;
 import com.viaversion.viaversion.api.minecraft.chunks.PaletteType;
 import com.viaversion.viaversion.api.type.Type;
 import io.netty.buffer.ByteBuf;
-import java.util.zip.Deflater;
+
+import java.util.zip.DataFormatException;
 
 import static com.viaversion.viaversion.api.minecraft.chunks.ChunkSection.SIZE;
 import static com.viaversion.viaversion.api.minecraft.chunks.ChunkSectionLight.LIGHT_LENGTH;
@@ -49,33 +51,41 @@ public class ChunkType1_7_6 extends Type<Chunk> {
         final boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
 
         final int size = calcSize(bitmask, addBitmask, hasSkyLight, biomes);
-        final byte[] data = new byte[size];
+        final ByteBuf uncompressed = buffer.alloc().buffer(size);
 
-        serialize(chunk, data, 0, addBitmask, hasSkyLight, biomes);
-
-        buffer.writeInt(chunk.getX());
-        buffer.writeInt(chunk.getZ());
-        buffer.writeBoolean(chunk.isFullChunk());
-        buffer.writeShort(bitmask);
-        buffer.writeShort(addBitmask);
-
-        final Deflater deflater = new Deflater();
-        byte[] compressedData;
-        int compressedSize;
         try {
-            deflater.setInput(data, 0, data.length);
-            deflater.finish();
-            compressedData = new byte[data.length];
-            compressedSize = deflater.deflate(compressedData);
-        } finally {
-            deflater.end();
-        }
+            serialize(chunk, uncompressed, addBitmask, hasSkyLight, biomes);
 
-        buffer.writeInt(compressedSize);
-        buffer.writeBytes(compressedData, 0, compressedSize);
+            buffer.writeInt(chunk.getX());
+            buffer.writeInt(chunk.getZ());
+            buffer.writeBoolean(chunk.isFullChunk());
+            buffer.writeShort(bitmask);
+            buffer.writeShort(addBitmask);
+
+            // Reserve 4 bytes for the compressed size
+            final int sizeIndex = buffer.writerIndex();
+            buffer.writeInt(0); // Placeholder for compressed size
+
+            // Write compressed data directly to output buffer
+            final int compressedStart = buffer.writerIndex();
+            try {
+                ThreadLocalCompressionProvider.deflate(uncompressed, buffer);
+            } catch (DataFormatException e) {
+                throw new RuntimeException("Failed to compress chunk data", e);
+            }
+            final int compressedSize = buffer.writerIndex() - compressedStart;
+
+            // Go back and write the compressed size
+            final int endIndex = buffer.writerIndex();
+            buffer.writerIndex(sizeIndex);
+            buffer.writeInt(compressedSize);
+            buffer.writerIndex(endIndex);
+        } finally {
+            uncompressed.release();
+        }
     }
 
-    public static int serialize(Chunk chunk, byte[] output, int offset, int addBitmask, boolean writeSkyLight, boolean biomes) {
+    public static void serialize(Chunk chunk, ByteBuf output, int addBitmask, boolean writeSkyLight, boolean biomes) {
         final ChunkSection[] sections = chunk.getSections();
         final int bitmask = chunk.getBitmask();
 
@@ -85,7 +95,7 @@ public class ChunkType1_7_6 extends Type<Chunk> {
                 final DataPalette palette = section.palette(PaletteType.BLOCKS);
                 for (int j = 0; j < SIZE; j++) {
                     final int block = palette.idAt(j);
-                    output[offset++] = (byte) ((block >> 4) & 0xFF);
+                    output.writeByte((block >> 4) & 0xFF);
                 }
             }
         }
@@ -97,7 +107,7 @@ public class ChunkType1_7_6 extends Type<Chunk> {
                 for (int j = 0; j < ChunkSection.SIZE; j += 2) {
                     final int meta1 = palette.idAt(j) & 0xF;
                     final int meta2 = palette.idAt(j + 1) & 0xF;
-                    output[offset++] = (byte) (meta1 | (meta2 << 4));
+                    output.writeByte(meta1 | (meta2 << 4));
                 }
             }
         }
@@ -105,8 +115,7 @@ public class ChunkType1_7_6 extends Type<Chunk> {
         for (int i = 0; i < 16; i++) {
             if ((bitmask & (1 << i)) != 0) {
                 final byte[] blockLight = sections[i].getLight().getBlockLight();
-                System.arraycopy(blockLight, 0, output, offset, LIGHT_LENGTH);
-                offset += LIGHT_LENGTH;
+                output.writeBytes(blockLight);
             }
         }
 
@@ -115,9 +124,11 @@ public class ChunkType1_7_6 extends Type<Chunk> {
                 if ((bitmask & (1 << i)) != 0) {
                     if (sections[i].getLight().hasSkyLight()) {
                         final byte[] skyLight = sections[i].getLight().getSkyLight();
-                        System.arraycopy(skyLight, 0, output, offset, LIGHT_LENGTH);
+                        output.writeBytes(skyLight);
+                    } else {
+                        // Write empty skylight data
+                        output.writeZero(LIGHT_LENGTH);
                     }
-                    offset += LIGHT_LENGTH;
                 }
             }
         }
@@ -130,7 +141,7 @@ public class ChunkType1_7_6 extends Type<Chunk> {
                     for (int j = 0; j < SIZE; j += 2) {
                         final int add1 = (palette.idAt(j) >> 12) & 0xF;
                         final int add2 = (palette.idAt(j + 1) >> 12) & 0xF;
-                        output[offset++] = (byte) (add1 | (add2 << 4));
+                        output.writeByte(add1 | (add2 << 4));
                     }
                 }
             }
@@ -139,11 +150,9 @@ public class ChunkType1_7_6 extends Type<Chunk> {
         if (biomes && chunk.getBiomeData() != null) {
             final int[] biomeData = chunk.getBiomeData();
             for (int biome : biomeData) {
-                output[offset++] = (byte) biome;
+                output.writeByte(biome);
             }
         }
-
-        return offset;
     }
 
     public static int calcSize(int bitmask, int addBitmask, boolean hasSkyLight, boolean biomes) {

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/Protocol1_8To1_7_6_10.java

@@ -38,6 +38,7 @@ import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.ScoreboardTracke
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.WorldBorderEmulator;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.task.WorldBorderUpdateTask;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.ProtocolStorables;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.ClientWorld;
 import com.viaversion.viaversion.api.platform.providers.ViaProviders;
@@ -122,8 +123,9 @@ public class Protocol1_8To1_7_6_10 extends BackwardsProtocol<ClientboundPackets1
 
     @Override
     public void init(UserConnection connection) {
-        connection.addEntityTracker(this.getClass(), new EntityTracker1_8(connection));
-        connection.addClientWorld(this.getClass(), new ClientWorld());
+        final ProtocolStorables storables = connection.storables(this);
+        storables.setEntityTracker(new EntityTracker1_8(connection));
+        storables.setClientWorld(new ClientWorld());
 
         connection.put(new InventoryTracker(connection));
         connection.put(new PlayerSessionStorage(connection));

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/data/ChatNewlineRewriter.java

@@ -26,6 +26,18 @@ import java.util.List;
 import java.util.Map;
 
 public class ChatNewlineRewriter {
+    private static final String[] STYLE_KEYS = {
+            "color",
+            "bold",
+            "italic",
+            "underlined",
+            "strikethrough",
+            "obfuscated",
+            "clickEvent",
+            "hoverEvent",
+            "insertion"
+    };
+
     public static List<JsonObject> splitChatComponentByNewline(JsonElement element) {
         return splitChatComponentByNewline(element, new JsonObject());
     }
@@ -47,8 +59,28 @@ public class ChatNewlineRewriter {
         }
 
         if (element.isJsonArray()) {
+            List<JsonObject> currentLine = new ArrayList<>();
+            JsonObject siblingStyle = inheritedStyle;
+            boolean foundRoot = false;
+
             for (JsonElement child : element.getAsJsonArray()) {
-                results.addAll(splitChatComponentByNewline(child, inheritedStyle));
+                List<JsonObject> splitParts = splitChatComponentByNewline(child, siblingStyle);
+                for (int i = 0; i < splitParts.size(); i++) {
+                    currentLine.add(splitParts.get(i));
+                    if (i < splitParts.size() - 1) {
+                        results.add(mergeLine(currentLine));
+                        currentLine.clear();
+                    }
+                }
+
+                if (!foundRoot && child != null && !child.isJsonNull()) {
+                    siblingStyle = rootStyle(inheritedStyle, child);
+                    foundRoot = true;
+                }
+            }
+
+            if (!currentLine.isEmpty()) {
+                results.add(mergeLine(currentLine));
             }
             return results;
         }
@@ -60,13 +92,7 @@ public class ChatNewlineRewriter {
         JsonObject obj = element.getAsJsonObject();
 
         // Build the style for this node: inherit first, then override with this object's style
-        JsonObject currentStyle = inheritedStyle.deepCopy();
-        for (Map.Entry<String, JsonElement> entry : obj.entrySet()) {
-            String key = entry.getKey();
-            if (!"text".equals(key) && !"extra".equals(key)) {
-                currentStyle.add(key, entry.getValue());
-            }
-        }
+        JsonObject currentStyle = mergeStyle(inheritedStyle, obj);
 
         // Gather components in order: base text then extra array
         List<JsonElement> ordered = new ArrayList<>();
@@ -81,12 +107,19 @@ public class ChatNewlineRewriter {
 
         // If there is no text/extra, return a single object with the style
         if (ordered.isEmpty()) {
-            results.add(currentStyle);
+            JsonObject baseComponent = copyComponentWithoutExtra(obj, currentStyle);
+            results.add(baseComponent != null ? baseComponent : currentStyle);
             return results;
         }
 
         // Build lines by concatenating split pieces
         List<JsonObject> currentLine = new ArrayList<>();
+        if (!obj.has("text")) {
+            JsonObject baseComponent = copyComponentWithoutExtra(obj, currentStyle);
+            if (baseComponent != null) {
+                currentLine.add(baseComponent);
+            }
+        }
         for (JsonElement part : ordered) {
             if (part == null || part.isJsonNull()) {
                 continue;
@@ -127,6 +160,55 @@ public class ChatNewlineRewriter {
         return results;
     }
 
+    private static JsonObject rootStyle(JsonObject inheritedStyle, JsonElement element) {
+        if (element == null || element.isJsonNull()) {
+            return inheritedStyle;
+        }
+        if (element.isJsonObject()) {
+            return mergeStyle(inheritedStyle, element.getAsJsonObject());
+        }
+        if (element.isJsonArray()) {
+            for (JsonElement child : element.getAsJsonArray()) {
+                if (child != null && !child.isJsonNull()) {
+                    return rootStyle(inheritedStyle, child);
+                }
+            }
+        }
+        return inheritedStyle;
+    }
+
+    private static JsonObject mergeStyle(JsonObject inheritedStyle, JsonObject obj) {
+        JsonObject currentStyle = inheritedStyle.deepCopy();
+        for (String key : STYLE_KEYS) {
+            if (obj.has(key)) {
+                currentStyle.add(key, obj.get(key).deepCopy());
+            }
+        }
+        return currentStyle;
+    }
+
+    private static JsonObject copyComponentWithoutExtra(JsonObject obj, JsonObject currentStyle) {
+        JsonObject component = currentStyle.deepCopy();
+        for (Map.Entry<String, JsonElement> entry : obj.entrySet()) {
+            String key = entry.getKey();
+            if ("extra".equals(key) || isStyleKey(key)) {
+                continue;
+            }
+
+            component.add(key, entry.getValue().deepCopy());
+        }
+        return component.size() == currentStyle.size() ? null : component;
+    }
+
+    private static boolean isStyleKey(String key) {
+        for (String styleKey : STYLE_KEYS) {
+            if (styleKey.equals(key)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     private static JsonObject mergeLine(List<JsonObject> lineParts) {
         if (lineParts.isEmpty()) {
             JsonObject empty = new JsonObject();
@@ -139,11 +221,14 @@ public class ChatNewlineRewriter {
             return first;
         }
 
+        JsonObject merged = new JsonObject();
+        merged.addProperty("text", "");
+
         JsonArray extra = new JsonArray();
-        for (int i = 1; i < lineParts.size(); i++) {
-            extra.add(lineParts.get(i));
+        for (JsonObject linePart : lineParts) {
+            extra.add(linePart);
         }
-        first.add("extra", extra);
-        return first;
+        merged.add("extra", extra);
+        return merged;
     }
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/CompressionHandlerProvider.java

@@ -20,7 +20,6 @@ package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.CompressionStatusTracker;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.platform.providers.Provider;
-import io.netty.channel.ChannelHandler;
 
 public abstract class CompressionHandlerProvider implements Provider {
 
@@ -28,23 +27,6 @@ public abstract class CompressionHandlerProvider implements Provider {
 
     public abstract void onTransformPacket(UserConnection user);
 
-    /**
-     * Creates the compression encoder
-     *
-     * @param compressor A nullable object that may present a native backend for compression (if available)
-     * @param threshold  The compression threshold
-     * @return The encoder
-     */
-    public abstract ChannelHandler getEncoder(Object compressor, int threshold);
-
-    /**
-     * Creates the compression decoder
-     *
-     * @param compressor A nullable object that may present a native backend for compression (if available)
-     * @param threshold  The compression threshold
-     * @return The decoder
-     */
-    public abstract ChannelHandler getDecoder(Object compressor, int threshold);
 
     public boolean isRemoveCompression(UserConnection user) {
         return user.get(CompressionStatusTracker.class).removeCompression;

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/compression/CompressionDecoder.java

@@ -17,18 +17,15 @@
  */
 package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression;
 
+import com.viaversion.viarewind.api.compression.ThreadLocalCompressionProvider;
 import com.viaversion.viaversion.api.type.Types;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import java.util.List;
-import java.util.zip.DataFormatException;
-import java.util.zip.Inflater;
 
 public class CompressionDecoder extends MessageToMessageDecoder<ByteBuf> {
-    private final Inflater inflater = new Inflater();
 
     private int threshold;
 
@@ -58,25 +55,12 @@ public class CompressionDecoder extends MessageToMessageDecoder<ByteBuf> {
             throw new DecoderException("Badly compressed packet - size of " + outLength + " is larger than protocol maximum of " + 2097152);
         }
 
-        inflate(ctx, in, outLength, out);
-    }
-
-    protected void inflate(final ChannelHandlerContext ctx, final ByteBuf source, final int outLength, final List<Object> out) throws DataFormatException {
-        ByteBuf temp = source;
-        if (!source.hasArray()) {
-            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(source);
-        } else {
-            source.retain();
-        }
-        ByteBuf output = ByteBufAllocator.DEFAULT.heapBuffer(outLength, outLength);
+        ByteBuf output = ctx.alloc().buffer(outLength);
         try {
-            this.inflater.setInput(temp.array(), temp.arrayOffset() + temp.readerIndex(), temp.readableBytes());
-            output.writerIndex(output.writerIndex() + this.inflater.inflate(output.array(), output.arrayOffset(), outLength));
+            ThreadLocalCompressionProvider.inflate(in, output, outLength);
             out.add(output.retain());
         } finally {
             output.release();
-            temp.release();
-            this.inflater.reset();
         }
     }
 

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/compression/CompressionEncoder.java

@@ -17,16 +17,13 @@
  */
 package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression;
 
+import com.viaversion.viarewind.api.compression.ThreadLocalCompressionProvider;
 import com.viaversion.viaversion.api.type.Types;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufAllocator;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToByteEncoder;
-import java.util.zip.DataFormatException;
-import java.util.zip.Deflater;
 
 public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
-    private final Deflater deflater = new Deflater();
 
     private int threshold;
 
@@ -48,32 +45,7 @@ public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
         }
 
         Types.VAR_INT.writePrimitive(out, frameLength);
-
-        deflate(in, out);
-    }
-
-    protected void deflate(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
-        ByteBuf temp = source;
-        if (!source.hasArray()) {
-            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(source);
-        } else {
-            source.retain();
-        }
-        ByteBuf output = ByteBufAllocator.DEFAULT.heapBuffer();
-        try {
-            this.deflater.setInput(temp.array(), temp.arrayOffset() + temp.readerIndex(), temp.readableBytes());
-            deflater.finish();
-
-            while (!deflater.finished()) {
-                output.ensureWritable(4096);
-                output.writerIndex(output.writerIndex() + this.deflater.deflate(output.array(), output.arrayOffset() + output.writerIndex(), output.writableBytes()));
-            }
-            destination.writeBytes(output);
-        } finally {
-            output.release();
-            temp.release();
-            this.deflater.reset();
-        }
+        ThreadLocalCompressionProvider.deflate(in, out);
     }
 
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/compression/TrackingCompressionHandlerProvider.java

@@ -21,28 +21,12 @@ import com.viaversion.viarewind.ViaRewind;
 import com.viaversion.viarewind.api.minecraft.netty.EmptyChannelHandler;
 import com.viaversion.viarewind.api.minecraft.netty.ForwardMessageToByteEncoder;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.CompressionHandlerProvider;
-import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression.velocity.VelocityCompressionDecoder;
-import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression.velocity.VelocityCompressionEncoder;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
-import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelPipeline;
 
 public class TrackingCompressionHandlerProvider extends CompressionHandlerProvider {
 
-    // Use Velocity's compression backend if ViaRewind is loaded on a Velocity server or a custom server software
-    // is shipping them in the classpath.
-    private static boolean velocityNatives;
-
-    static {
-        try {
-            Class.forName("com.velocitypowered.natives.compression.VelocityCompressor");
-            velocityNatives = true;
-        } catch (final ClassNotFoundException ignored) {
-            velocityNatives = false;
-        }
-    }
-
     @Override
     public void setCompressionThreshold(UserConnection user, int threshold) {
         final ChannelPipeline pipeline = user.getChannel().pipeline();
@@ -51,17 +35,12 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
             return;
         }
 
-        Object compressor = null;
-        if (velocityNatives) {
-            compressor = com.velocitypowered.natives.util.Natives.compress.get().create(-1);
-        }
-
         final String compressHandlerName = ViaRewind.getPlatform().compressHandlerName();
         final CompressionEncoder encoder = (CompressionEncoder) pipeline.get(compressHandlerName);
         if (encoder != null) {
             encoder.setThreshold(threshold);
         } else {
-            pipeline.addBefore(Via.getManager().getInjector().getEncoderName(), compressHandlerName, getEncoder(compressor, threshold));
+            pipeline.addBefore(Via.getManager().getInjector().getEncoderName(), compressHandlerName, new CompressionEncoder(threshold));
         }
 
         final String decompressHandlerName = ViaRewind.getPlatform().decompressHandlerName();
@@ -69,7 +48,7 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
         if (decoder != null) {
             decoder.setThreshold(threshold);
         } else {
-            pipeline.addBefore(Via.getManager().getInjector().getDecoderName(), decompressHandlerName, getDecoder(compressor, threshold));
+            pipeline.addBefore(Via.getManager().getInjector().getDecoderName(), decompressHandlerName, new CompressionDecoder(threshold));
         }
     }
 
@@ -96,22 +75,5 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
         }
     }
 
-    @Override
-    public ChannelHandler getEncoder(final Object compressor, int threshold) {
-        if (velocityNatives) {
-            return new VelocityCompressionEncoder(threshold, (com.velocitypowered.natives.compression.VelocityCompressor) compressor);
-        } else {
-            return new CompressionEncoder(threshold);
-        }
-    }
-
-    @Override
-    public ChannelHandler getDecoder(final Object compressor, int threshold) {
-        if (velocityNatives) {
-            return new VelocityCompressionDecoder(threshold, (com.velocitypowered.natives.compression.VelocityCompressor) compressor);
-        } else {
-            return new CompressionDecoder(threshold);
-        }
-    }
 
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/compression/velocity/VelocityCompressionDecoder.java

@@ -1,47 +0,0 @@
-/*
- * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2026 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.viarewind.protocol.v1_8to1_7_6_10.provider.compression.velocity;
-
-import com.velocitypowered.natives.compression.VelocityCompressor;
-import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression.CompressionDecoder;
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandlerContext;
-import java.util.List;
-import java.util.zip.DataFormatException;
-
-public final class VelocityCompressionDecoder extends CompressionDecoder {
-
-    private final VelocityCompressor compressor;
-
-    public VelocityCompressionDecoder(final int threshold, final VelocityCompressor compressor) {
-        super(threshold);
-        this.compressor = compressor;
-    }
-
-    @Override
-    protected void inflate(final ChannelHandlerContext ctx, final ByteBuf source, final int outLength, final List<Object> out) throws DataFormatException {
-        ByteBuf output = ctx.alloc().buffer(outLength);
-        try {
-            this.compressor.inflate(source, output, outLength);
-            out.add(output.retain());
-        } finally {
-            output.release();
-        }
-    }
-
-}

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/provider/compression/velocity/VelocityCompressionEncoder.java

@@ -1,39 +0,0 @@
-/*
- * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2026 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.viarewind.protocol.v1_8to1_7_6_10.provider.compression.velocity;
-
-import com.velocitypowered.natives.compression.VelocityCompressor;
-import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.compression.CompressionEncoder;
-import io.netty.buffer.ByteBuf;
-import java.util.zip.DataFormatException;
-
-public final class VelocityCompressionEncoder extends CompressionEncoder {
-
-    private final VelocityCompressor compressor;
-
-    public VelocityCompressionEncoder(final int threshold, final VelocityCompressor compressor) {
-        super(threshold);
-        this.compressor = compressor;
-    }
-
-    @Override
-    protected void deflate(final ByteBuf source, final ByteBuf destination) throws DataFormatException {
-        this.compressor.deflate(source, destination);
-    }
-
-}

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/BlockItemPacketRewriter1_8.java

@@ -113,7 +113,7 @@ public class BlockItemPacketRewriter1_8 extends VRBlockItemRewriter<ClientboundP
                     final Item item = wrapper.get(RewindTypes.COMPRESSED_NBT_ITEM, 0);
                     playerSession.setPlayerEquipment(wrapper.user().getProtocolInfo().getUuid(), item, 8 - slot);
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (tracker.isSpectator()) { // Spectator mode didn't exist in 1.7.10
                         wrapper.cancel();
                     }
@@ -148,7 +148,7 @@ public class BlockItemPacketRewriter1_8 extends VRBlockItemRewriter<ClientboundP
                     if (windowId != 0) {
                         return;
                     }
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     final UUID userId = wrapper.user().getProtocolInfo().getUuid();
 
                     final Item[] items = wrapper.get(RewindTypes.COMPRESSED_NBT_ITEM_ARRAY, 0);

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/EntityPacketRewriter1_8.java

@@ -76,7 +76,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                         }
                     }
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     tracker.addPlayer(entityId, wrapper.user().getProtocolInfo().getUuid());
 
                     tracker.setClientEntityGameMode(wrapper.get(Types.UNSIGNED_BYTE, 0));
@@ -275,7 +275,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                         final byte pitch = wrapper.get(Types.BYTE, 1);
                         final byte yaw = wrapper.get(Types.BYTE, 0);
                         final byte headYaw = wrapper.get(Types.BYTE, 2);
-                        final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                        final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                         final VirtualHologramEntity hologram = tracker.getHolograms().get(entityId);
 
                         hologram.setPosition(x / 32.0, y / 32.0, z / 32.0);
@@ -314,7 +314,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
 
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (gameProfile != null && gameProfile.gamemode == 3) { // Spectator mode
                         for (short i = 0; i < 5; i++) {
                             final PacketWrapper entityEquipment = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_EQUIPPED_ITEM, wrapper.user());
@@ -354,7 +354,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 handler(wrapper -> protocol.getItemRewriter().handleItemToClient(wrapper.user(), wrapper.get(RewindTypes.COMPRESSED_NBT_ITEM, 0)));
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     final int id = wrapper.get(Types.INT, 0);
 
                     final int limit = tracker.clientEntityId() == id ? 3 : 4;
@@ -364,7 +364,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 });
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     final short slot = wrapper.get(Types.SHORT, 0);
                     final UUID uuid = tracker.getPlayerUUID(wrapper.get(Types.INT, 0));
                     if (uuid == null) {
@@ -396,7 +396,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 map(Types.VAR_INT, Types.INT); // Collected Entity id
                 map(Types.VAR_INT, Types.INT); // Collector Entity id
 
-                handler(wrapper -> wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class).removeEntity(wrapper.get(Types.INT, 0)));
+                handler(wrapper -> wrapper.user().getEntityTracker(protocol).removeEntity(wrapper.get(Types.INT, 0)));
             }
         });
 
@@ -424,7 +424,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 read(Types.BOOLEAN); // On ground
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
                     final VirtualHologramEntity hologram = tracker.getHolograms().get(wrapper.get(Types.INT, 0));
                     if (hologram != null) {
@@ -448,7 +448,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 read(Types.BOOLEAN); // On ground
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
                     final VirtualHologramEntity hologram = tracker.getHolograms().get(wrapper.get(Types.INT, 0));
                     if (hologram != null) {
@@ -474,7 +474,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 read(Types.BOOLEAN); // On ground
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
                     final VirtualHologramEntity hologram = tracker.getHolograms().get(wrapper.get(Types.INT, 0));
                     if (hologram != null) {
@@ -506,7 +506,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 handler(wrapper -> {
                     final int entityId = wrapper.get(Types.INT, 0);
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (tracker.entityType(entityId) == EntityTypes1_8.EntityType.ABSTRACT_MINECART) { // TODO | Realign all entities?
                         int y = wrapper.get(Types.INT, 2);
                         y += 12;
@@ -537,7 +537,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 map(Types.BYTE); // Head yaw
 
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
                     final VirtualHologramEntity hologram = tracker.getHolograms().get(wrapper.get(Types.INT, 0));
                     if (hologram != null) {
@@ -559,7 +559,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 handler(wrapper -> {
                     final boolean leash = wrapper.get(Types.BOOLEAN, 0);
                     if (!leash) {
-                        final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                        final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
                         final int passenger = wrapper.get(Types.INT, 0);
                         final int vehicle = wrapper.get(Types.INT, 1);
@@ -594,7 +594,7 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
             public void register() {
                 map(Types.VAR_INT, Types.INT); // Entity id
                 handler(wrapper -> {
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (tracker.getHolograms().containsKey(wrapper.get(Types.INT, 0))) { // Don't handle properties for hologram emulation
                         wrapper.cancel();
                         return;

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/PlayerPacketRewriter1_8.java

@@ -38,6 +38,7 @@ import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.InventoryTracker
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.PlayerSessionStorage;
 import com.viaversion.viarewind.utils.ChatUtil;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.minecraft.BlockPosition;
 import com.viaversion.viaversion.api.minecraft.ClientWorld;
 import com.viaversion.viaversion.api.minecraft.GameProfile;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
@@ -48,6 +49,7 @@ import com.viaversion.viaversion.api.rewriter.RewriterBase;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.libs.gson.JsonElement;
 import com.viaversion.viaversion.libs.gson.JsonObject;
+import com.viaversion.viaversion.libs.gson.JsonPrimitive;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_8;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ServerboundPackets1_8;
 import com.viaversion.viaversion.util.ComponentUtil;
@@ -127,13 +129,13 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                         }
                     }
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     tracker.setClientEntityGameMode(wrapper.get(Types.UNSIGNED_BYTE, 1));
 
                     final int dimension = wrapper.get(Types.INT, 0);
 
                     // Clear entities on dimension change and re-track player
-                    final ClientWorld world = wrapper.user().getClientWorld(Protocol1_8To1_7_6_10.class);
+                    final ClientWorld world = wrapper.user().storables(protocol).clientWorld();
                     if (world.setEnvironment(dimension)) {
                         tracker.clearEntities();
                         tracker.addPlayer(tracker.clientEntityId(), wrapper.user().getProtocolInfo().getUuid());
@@ -194,7 +196,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
 
                     wrapper.write(Types.BOOLEAN, playerSession.onGround);
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (!Objects.equals(tracker.spectatingClientEntityId, tracker.clientEntityIdOrNull())) {
                         wrapper.cancel();
                     }
@@ -220,7 +222,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                     if (wrapper.get(Types.UNSIGNED_BYTE, 0) != 3) return; // Change game mode
                     int gameMode = wrapper.get(Types.FLOAT, 0).intValue();
 
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (gameMode == 3 || tracker.isSpectator()) {
                         UUID myId = wrapper.user().getProtocolInfo().getUuid();
                         Item[] equipment = new Item[4];
@@ -292,7 +294,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                     }
 
                     if (gamemode == 3 || gameProfile.gamemode == 3) {
-                        EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                        EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                         int entityId = tracker.getPlayerEntityId(uuid);
                         boolean isOwnPlayer = entityId == tracker.clientEntityId();
                         if (entityId != -1) {
@@ -445,7 +447,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
             wrapper.cancel();
             final int entityId = wrapper.read(Types.VAR_INT);
 
-            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
             if (tracker.spectatingClientEntityId != entityId) {
                 tracker.setSpectating(entityId);
             }
@@ -506,12 +508,18 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
 
         protocol.registerServerbound(ServerboundPackets1_7_2_5.CHAT, wrapper -> {
             final String message = wrapper.passthrough(Types.STRING);
-            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
             if (tracker.isSpectator() && message.toLowerCase().startsWith("/stp ")) { // TODO add setting
                 String username = message.split(" ")[1];
                 final GameProfileStorage storage = wrapper.user().get(GameProfileStorage.class);
 
-                final GameProfileStorage.GameProfile profile = storage.get(username, true);
+                // Multiple players with the same name may exist. This will only represent
+                // fake players so it's fine to just pick the first one.
+                List<GameProfileStorage.GameProfile> profiles = storage.get(username, true);
+                if (profiles.isEmpty()) {
+                    return;
+                }
+                final GameProfileStorage.GameProfile profile = profiles.get(0);
                 if (profile != null && profile.uuid != null) {
                     wrapper.cancel();
 
@@ -529,10 +537,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                 map(Types.BYTE, Types.VAR_INT); // Mode
                 handler(wrapper -> {
                     final int mode = wrapper.get(Types.VAR_INT, 1);
-                    if (mode != 0) {
-                        return;
-                    }
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     final int entityId = tracker.getHologramIdWithExtra(wrapper.get(Types.VAR_INT, 0));
                     final PlayerSessionStorage position = wrapper.user().get(PlayerSessionStorage.class);
 
@@ -541,6 +546,11 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                     }
 
                     wrapper.set(Types.VAR_INT, 0, entityId);
+
+                    if (mode != 0) {
+                        return;
+                    }
+
                     final AABB boundingBox = tracker.getHolograms().get(entityId).getBoundingBox();
 
                     Vector3d pos = new Vector3d(position.getPosX(), position.getPosY() + 1.8, position.getPosZ());
@@ -608,6 +618,16 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
             protected void register() {
                 map(Types.VAR_INT); // Status
                 map(RewindTypes.U_BYTE_POSITION, Types.BLOCK_POSITION1_8); // Position
+                handler(wrapper -> {
+                    // 1.7 uses 255 as "no face"
+                    // 1.8 changed this to only be in the range EnumFacing range (0-5) and uses DOWN when no face is used
+                    // This properly rewrites invalid values to the 1.8 equivalent
+                    int face = wrapper.read(Types.UNSIGNED_BYTE);
+                    if (face > 5) {
+                        face = 0;
+                    }
+                    wrapper.write(Types.UNSIGNED_BYTE, (short) face);
+                });
             }
         });
 
@@ -618,6 +638,16 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                 map(Types.BYTE); // Direction
                 map(RewindTypes.COMPRESSED_NBT_ITEM, Types.ITEM1_8); // Item
 
+                handler(wrapper -> {
+                    final BlockPosition position = wrapper.get(Types.BLOCK_POSITION1_8, 0);
+                    final byte direction = wrapper.get(Types.BYTE, 0);
+                    // 1.7 serializes the Y component as an unsigned byte, turning the
+                    // use-in-air position from (-1, -1, -1) into (-1, 255, -1).
+                    // we change that back to -1 for Y like 1.8 clients
+                    if (position.x() == -1 && position.y() == 255 && position.z() == -1 && direction == -1) {
+                        wrapper.set(Types.BLOCK_POSITION1_8, 0, new BlockPosition(-1, -1, -1));
+                    }
+                });
                 handler(wrapper -> protocol.getItemRewriter().handleItemToServer(wrapper.user(), wrapper.get(Types.ITEM1_8, 0)));
             }
         });
@@ -690,7 +720,7 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                     if (!unmount) {
                         return;
                     }
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
                     if (tracker.spectatingClientEntityId != tracker.clientEntityId()) {
                         PacketWrapper sneakPacket = PacketWrapper.create(ServerboundPackets1_8.PLAYER_COMMAND, wrapper.user());
                         sneakPacket.write(Types.VAR_INT, tracker.clientEntityId());
@@ -770,6 +800,8 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
             }
         });
 
+        // 1.7.10 custom payload constructor (String, ByteBuf) uses byteBuf.array(), so it sends the whole backing array capacity, not only the written bytes
+        // After reading the proper packet data we discard the remaining bytes
         protocol.registerServerbound(ServerboundPackets1_7_2_5.CUSTOM_PAYLOAD, new PacketHandlers() {
             @Override
             public void register() {
@@ -780,7 +812,27 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                     switch (channel) {
                         case "MC|TrSel": {
                             wrapper.passthrough(Types.INT);
-                            wrapper.read(Types.REMAINING_BYTES); // unused data ???
+                            wrapper.read(Types.REMAINING_BYTES); // Discard remaining bytes
+                            break;
+                        }
+                        case "MC|AdvCdm": {
+                            final byte commandBlockType = wrapper.passthrough(Types.BYTE);
+                            if (commandBlockType == 0) { // Block
+                                wrapper.passthrough(Types.INT); // X
+                                wrapper.passthrough(Types.INT); // Y
+                                wrapper.passthrough(Types.INT); // Z
+                            } else if (commandBlockType == 1) { // Minecart
+                                wrapper.passthrough(Types.INT); // Entity id
+                            }
+                            wrapper.passthrough(Types.STRING); // Command
+                            wrapper.write(Types.BOOLEAN, true); // Track output, added in 1.8, default to true
+                            wrapper.read(Types.REMAINING_BYTES); // Discard remaining bytes
+                            break;
+                        }
+                        case "MC|Beacon": {
+                            wrapper.passthrough(Types.INT); // Primary effect
+                            wrapper.passthrough(Types.INT); // Secondary effect
+                            wrapper.read(Types.REMAINING_BYTES); // Discard remaining bytes
                             break;
                         }
                         case "MC|ItemName": {
@@ -797,17 +849,28 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
                         }
                         case "MC|BEdit":
                         case "MC|BSign": {
+                            final boolean signBook = channel.equals("MC|BSign");
                             final Item book = wrapper.read(RewindTypes.COMPRESSED_NBT_ITEM);
-                            CompoundTag tag = book.tag();
-                            if (tag != null && tag.contains("pages")) {
-                                ListTag<StringTag> pages = tag.getListTag("pages", StringTag.class);
-                                for (int i = 0; i < pages.size(); i++) {
-                                    StringTag page = pages.get(i);
-                                    String value = page.getValue();
-                                    value = ComponentUtil.legacyToJsonString(value);
-                                    page.setValue(value);
+                            wrapper.read(Types.REMAINING_BYTES); // Discard remaining bytes
+
+                            if (book == null) {
+                                wrapper.write(Types.ITEM1_8, null);
+                                break;
+                            }
+
+                            final CompoundTag tag = book.tag();
+                            if (signBook && tag != null && tag.contains("pages")) {
+                                final ListTag<StringTag> pages = tag.getListTag("pages", StringTag.class);
+                                if (pages != null) {
+                                    for (int i = 0; i < pages.size(); i++) {
+                                        final StringTag page = pages.get(i);
+                                        String value = page.getValue();
+                                        value = new JsonPrimitive(value).toString();
+                                        page.setValue(value);
+                                    }
                                 }
                             }
+                            protocol.getItemRewriter().handleItemToServer(wrapper.user(), book);
                             wrapper.write(Types.ITEM1_8, book);
                             break;
                         }

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/ScoreboardPacketRewriter1_8.java

@@ -174,7 +174,7 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
             }
 
             final ScoreboardTracker scoreboard = wrapper.user().get(ScoreboardTracker.class);
-            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
+            final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(protocol);
 
             final byte mode = wrapper.passthrough(Types.BYTE);
             if (mode != 0 && !scoreboard.teamExists(team)) {

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/WorldPacketRewriter1_8.java

@@ -47,7 +47,7 @@ public class WorldPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
     @Override
     protected void registerPackets() {
         protocol.registerClientbound(ClientboundPackets1_8.LEVEL_CHUNK, wrapper -> {
-            final ClientWorld world = wrapper.user().getClientWorld(Protocol1_8To1_7_6_10.class);
+            final ClientWorld world = wrapper.user().storables(protocol).clientWorld();
             final Chunk chunk = wrapper.read(ChunkType1_8.forEnvironment(world.getEnvironment()));
             protocol.getItemRewriter().handleChunk(chunk);
 

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/storage/EntityTracker1_8.java

@@ -22,6 +22,7 @@ import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ServerboundPa
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.Protocol1_8To1_7_6_10;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.data.VirtualHologramEntity;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.entity.TrackedEntity;
 import com.viaversion.viaversion.api.minecraft.entities.EntityType;
 import com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_8;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
@@ -68,17 +69,15 @@ public class EntityTracker1_8 extends EntityTrackerBase {
     }
 
     @Override
-    public void addEntity(int id, EntityType type) {
-        super.addEntity(id, type);
+    public TrackedEntity addEntity(int id, EntityType type) {
         if (type == EntityTypes1_8.EntityType.ARMOR_STAND) {
             holograms.put(id, new VirtualHologramEntity(user(), id));
         }
+        return super.addEntity(id, type);
     }
 
     @Override
-    public void removeEntity(int entityId) {
-        super.removeEntity(entityId);
-
+    public TrackedEntity removeEntity(int entityId) {
         final VirtualHologramEntity hologram = holograms.get(entityId);
         if (hologram != null) {
             hologram.deleteEntity();
@@ -95,6 +94,7 @@ public class EntityTracker1_8 extends EntityTrackerBase {
             entityUUIDToId.removeInt(playerId);
             user().get(PlayerSessionStorage.class).getPlayerEquipment().remove(playerId);
         }
+        return super.removeEntity(entityId);
     }
 
     @Override
@@ -222,17 +222,16 @@ public class EntityTracker1_8 extends EntityTrackerBase {
 
     public void checkNametagVisbility(final String username) {
         final GameProfileStorage profileStorage = user().get(GameProfileStorage.class);
-        final GameProfileStorage.GameProfile profile = profileStorage.get(username, false);
-        if (profile == null) {
-            return;
-        }
+        final List<GameProfileStorage.GameProfile> profiles = profileStorage.get(username, false);
 
-        final int entityId = getPlayerEntityId(profile.uuid);
-        if (entityId == -1) {
-            return;
-        }
+        for (GameProfileStorage.GameProfile profile : profiles) {
+            final int entityId = getPlayerEntityId(profile.uuid);
+            if (entityId == -1) {
+                return;
+            }
 
-        checkNametagVisibility(entityId);
+            checkNametagVisibility(entityId);
+        }
     }
 
     private boolean isPlayerNametagHidden(final int entityId) {

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/storage/GameProfileStorage.java

@@ -17,6 +17,10 @@
  */
 package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage;
 
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ListMultimap;
+import com.google.common.collect.Multimap;
 import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.ListTag;
 import com.viaversion.nbt.tag.StringTag;
@@ -34,6 +38,7 @@ import java.util.UUID;
 
 public class GameProfileStorage extends StoredObject {
     private final Map<UUID, GameProfile> properties = new HashMap<>();
+    private final ListMultimap<String, GameProfile> nameToProfile = ArrayListMultimap.create();
 
     public GameProfileStorage(UserConnection user) {
         super(user);
@@ -42,6 +47,7 @@ public class GameProfileStorage extends StoredObject {
     public GameProfile put(UUID uuid, String name, String displayName, int ping, int gamemode) {
         GameProfile gameProfile = new GameProfile(uuid, name, displayName, ping, gamemode);
         properties.put(uuid, gameProfile);
+        nameToProfile.put(name, gameProfile);
         return gameProfile;
     }
 
@@ -49,19 +55,9 @@ public class GameProfileStorage extends StoredObject {
         return properties.get(uuid);
     }
 
-    public GameProfile get(String name, boolean ignoreCase) {
+    public List<GameProfile> get(String name, boolean ignoreCase) {
         if (ignoreCase) name = name.toLowerCase();
-
-        for (GameProfile profile : properties.values()) {
-            if (profile.name == null) continue;
-
-            String n = ignoreCase ? profile.name.toLowerCase() : profile.name;
-
-            if (n.equals(name)) {
-                return profile;
-            }
-        }
-        return null;
+        return nameToProfile.get(name);
     }
 
     public List<GameProfile> getAllWithPrefix(String prefix, boolean ignoreCase) {
@@ -81,7 +77,11 @@ public class GameProfileStorage extends StoredObject {
     }
 
     public GameProfile remove(UUID uuid) {
-        return properties.remove(uuid);
+        GameProfile removedProfile = properties.remove(uuid);
+        if (removedProfile != null) {
+            nameToProfile.get(removedProfile.name).remove(removedProfile);
+        }
+        return removedProfile;
     }
 
 

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/storage/ScoreboardTracker.java

@@ -140,37 +140,43 @@ public class ScoreboardTracker extends StoredObject {
     public String sendTeamForScore(String score) {
         if (score.length() <= 16) return score;
         if (scoreTeams.containsKey(score)) return scoreTeams.get(score).name;
-        int l = 16;
-        int i = Math.min(16, score.length() - 16);
-        String name = score.substring(i, i + l);
-        while (scoreTeamNames.contains(name) || teams.containsKey(name)) {
-            i--;
-            while (score.length() - l - i > 16) {
-                l--;
-                if (l < 1) return score;
-                i = Math.min(16, score.length() - l);
+
+        // Find the longest window score[i, i+l) that:
+        // - is not already claimed as a team name
+        // - keeps prefix (score[0,i)) at most 16 chars i <= 16
+        // - keeps suffix (score[i+l, end)) at most 16 chars score.length()-l-i <= 16
+        for (int l = 16; l >= 1; l--) {
+            final int iMax = Math.min(16, score.length() - l);
+            final int iMin = Math.max(0, score.length() - l - 16);
+            for (int i = iMax; i >= iMin; i--) {
+                final String name = score.substring(i, i + l);
+                if (scoreTeamNames.contains(name) || teams.containsKey(name)) {
+                    continue;
+                }
+
+                final String prefix = score.substring(0, i);
+                final String suffix = i + l >= score.length() ? "" : score.substring(i + l);
+
+                final ScoreTeam scoreTeam = new ScoreTeam(name, prefix, suffix);
+                scoreTeams.put(score, scoreTeam);
+                scoreTeamNames.add(name);
+
+                final PacketWrapper teamPacket = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_PLAYER_TEAM, getUser());
+                teamPacket.write(Types.STRING, name);
+                teamPacket.write(Types.BYTE, (byte) 0);
+                teamPacket.write(Types.STRING, "ViaRewind");
+                teamPacket.write(Types.STRING, prefix);
+                teamPacket.write(Types.STRING, suffix);
+                teamPacket.write(Types.BYTE, (byte) 0);
+                teamPacket.write(Types.SHORT, (short) 1);
+                teamPacket.write(Types.STRING, name);
+                teamPacket.send(Protocol1_8To1_7_6_10.class);
+
+                return name;
             }
-            name = score.substring(i, i + l);
         }
-        String prefix = score.substring(0, i);
-        String suffix = i + l >= score.length() ? "" : score.substring(i + l);
 
-        ScoreTeam scoreTeam = new ScoreTeam(name, prefix, suffix);
-        scoreTeams.put(score, scoreTeam);
-        scoreTeamNames.add(name);
-
-        PacketWrapper teamPacket = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_PLAYER_TEAM, getUser());
-        teamPacket.write(Types.STRING, name);
-        teamPacket.write(Types.BYTE, (byte) 0);
-        teamPacket.write(Types.STRING, "ViaRewind");
-        teamPacket.write(Types.STRING, prefix);
-        teamPacket.write(Types.STRING, suffix);
-        teamPacket.write(Types.BYTE, (byte) 0);
-        teamPacket.write(Types.SHORT, (short) 1);
-        teamPacket.write(Types.STRING, name);
-        teamPacket.send(Protocol1_8To1_7_6_10.class);
-
-        return name;
+        return score;
     }
 
     public String removeTeamForScore(String score) {

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/task/WorldBorderUpdateTask.java

@@ -35,6 +35,9 @@ public class WorldBorderUpdateTask implements Runnable {
     public void run() {
         for (UserConnection connection : Via.getManager().getConnectionManager().getConnections()) {
             final WorldBorderEmulator worldBorderEmulatorTracker = connection.get(WorldBorderEmulator.class);
+            if (worldBorderEmulatorTracker == null) {
+                continue;
+            }
             if (!worldBorderEmulatorTracker.isInit()) continue;
 
             final PlayerSessionStorage playerSession = connection.get(PlayerSessionStorage.class);

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/Protocol1_9To1_8.java

@@ -26,14 +26,17 @@ import com.viaversion.viarewind.protocol.v1_9to1_8.rewriter.PlayerPacketRewriter
 import com.viaversion.viarewind.protocol.v1_9to1_8.rewriter.WorldPacketRewriter1_9;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.BlockPlaceDestroyTracker;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.BossBarStorage;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.CommandBlockStateStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.CooldownStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.EntityTracker1_9;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.LevitationStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.PlayerPositionTracker;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.LastTitle;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.WindowTracker;
 import com.viaversion.viarewind.protocol.v1_9to1_8.task.CooldownIndicatorTask;
 import com.viaversion.viarewind.protocol.v1_9to1_8.task.LevitationUpdateTask;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.ProtocolStorables;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.ClientWorld;
 import com.viaversion.viaversion.api.platform.providers.ViaProviders;
@@ -51,7 +54,7 @@ public class Protocol1_9To1_8 extends BackwardsProtocol<ClientboundPackets1_9, C
     public static final ValueTransformer<Double, Integer> DOUBLE_TO_INT_TIMES_32 = new ValueTransformer<>(Types.INT) {
         @Override
         public Integer transform(PacketWrapper wrapper, Double inputValue) {
-            return (int) (inputValue * 32.0D);
+            return (int) Math.round(inputValue * 32.0D);
         }
     };
     public static final ValueTransformer<Float, Byte> DEGREES_TO_ANGLE = new ValueTransformer<>(Types.BYTE) {
@@ -61,7 +64,7 @@ public class Protocol1_9To1_8 extends BackwardsProtocol<ClientboundPackets1_9, C
         }
     };
 
-    public static final RewindMappingData MAPPINGS = new RewindMappingData("1.9.4", "1.8");
+    public static final RewindMappingData MAPPINGS = new RewindMappingData("1.9", "1.8");
 
     private final BlockItemPacketRewriter1_9 itemRewriter = new BlockItemPacketRewriter1_9(this);
     private final EntityPacketRewriter1_9 entityRewriter = new EntityPacketRewriter1_9(this);
@@ -80,15 +83,18 @@ public class Protocol1_9To1_8 extends BackwardsProtocol<ClientboundPackets1_9, C
 
     @Override
     public void init(UserConnection connection) {
-        connection.addEntityTracker(this.getClass(), new EntityTracker1_9(connection));
-        connection.addClientWorld(this.getClass(), new ClientWorld());
+        final ProtocolStorables storables = connection.storables(this);
+        storables.setEntityTracker(new EntityTracker1_9(connection));
+        storables.setClientWorld(new ClientWorld());
 
         connection.put(new WindowTracker(connection));
         connection.put(new LevitationStorage());
         connection.put(new PlayerPositionTracker());
         connection.put(new CooldownStorage());
+        connection.put(new LastTitle());
         connection.put(new BlockPlaceDestroyTracker());
         connection.put(new BossBarStorage(connection));
+        connection.put(new CommandBlockStateStorage());
     }
 
     @Override

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/cooldown/TitleCooldownVisualization.java

@@ -18,21 +18,23 @@
 package com.viaversion.viarewind.protocol.v1_9to1_8.cooldown;
 
 import com.viaversion.viarewind.protocol.v1_9to1_8.Protocol1_9To1_8;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.LastTitle;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.libs.gson.JsonPrimitive;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_8;
-import java.util.function.Consumer;
 
 public class TitleCooldownVisualization implements CooldownVisualization {
 
-    private static final int ACTION_SET_TITLE = 0;
-    private static final int ACTION_SET_SUBTITLE = 1;
-    private static final int ACTION_SET_TIMES_AND_DISPLAY = 2;
-    private static final int ACTION_HIDE = 3;
+    public static final int ACTION_SET_TITLE = 0;
+    public static final int ACTION_SET_SUBTITLE = 1;
+    public static final int ACTION_SET_TIMES_AND_DISPLAY = 2;
+    public static final int ACTION_HIDE = 3;
+    public static final int ACTION_RESET = 4;
 
     private final UserConnection user;
+    private boolean visible;
 
     public TitleCooldownVisualization(UserConnection user) {
         this.user = user;
@@ -40,28 +42,71 @@ public class TitleCooldownVisualization implements CooldownVisualization {
 
     @Override
     public void show(double progress) throws Exception {
-        final String text = CooldownVisualization.buildProgressText("˙", progress);
+        final LastTitle title = this.user.get(LastTitle.class);
+        if (this.visible && title.isVisible()) {
+            this.restoreTitle(title);
+            return;
+        }
 
-        sendTitlePacket(ACTION_SET_TITLE, wrapper -> wrapper.write(Types.COMPONENT, new JsonPrimitive("")));
-        sendTitlePacket(ACTION_SET_SUBTITLE, wrapper -> wrapper.write(Types.COMPONENT, new JsonPrimitive(text)));
-        sendTitlePacket(ACTION_SET_TIMES_AND_DISPLAY, wrapper -> {
-            wrapper.write(Types.INT, 0);
-            wrapper.write(Types.INT, 2);
-            wrapper.write(Types.INT, 5);
-        });
+        final PacketWrapper setTitle = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        setTitle.write(Types.VAR_INT, ACTION_SET_TITLE);
+        setTitle.write(Types.COMPONENT, new JsonPrimitive(""));
+        setTitle.send(Protocol1_9To1_8.class);
+
+        final PacketWrapper setSubtitle = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        setSubtitle.write(Types.VAR_INT, ACTION_SET_SUBTITLE);
+        setSubtitle.write(Types.COMPONENT, new JsonPrimitive(CooldownVisualization.buildProgressText("˙", progress)));
+        setSubtitle.send(Protocol1_9To1_8.class);
+
+        final PacketWrapper setTitleTimes = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        setTitleTimes.write(Types.VAR_INT, ACTION_SET_TIMES_AND_DISPLAY);
+        setTitleTimes.write(Types.INT, 0);
+        setTitleTimes.write(Types.INT, 2);
+        setTitleTimes.write(Types.INT, 5);
+        setTitleTimes.send(Protocol1_9To1_8.class);
+        this.visible = true;
     }
 
     @Override
     public void hide() throws Exception {
-        sendTitlePacket(ACTION_HIDE, wrapper -> {
-        });
+        if (!this.visible) {
+            return;
+        }
+
+        final LastTitle title = this.user.get(LastTitle.class);
+        if (title.isVisible()) {
+            this.restoreTitle(title);
+            return;
+        }
+
+        final PacketWrapper hideTitle = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        hideTitle.write(Types.VAR_INT, ACTION_HIDE);
+        hideTitle.send(Protocol1_9To1_8.class);
+        this.visible = false;
     }
 
-    private void sendTitlePacket(int action, Consumer<PacketWrapper> writer) {
-        final PacketWrapper title = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
-        title.write(Types.VAR_INT, action);
-        writer.accept(title);
-        title.scheduleSend(Protocol1_9To1_8.class);
+    private void restoreTitle(final LastTitle title) {
+        final PacketWrapper setTitleTimes = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        setTitleTimes.write(Types.VAR_INT, ACTION_SET_TIMES_AND_DISPLAY);
+        final int[] times = title.remainingTimes();
+        setTitleTimes.write(Types.INT, times[0]);
+        setTitleTimes.write(Types.INT, times[1]);
+        setTitleTimes.write(Types.INT, times[2]);
+        setTitleTimes.send(Protocol1_9To1_8.class);
+
+        if (title.subtitle() != null) {
+            final PacketWrapper setSubtitle = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+            setSubtitle.write(Types.VAR_INT, ACTION_SET_SUBTITLE);
+            setSubtitle.write(Types.COMPONENT, title.subtitle());
+            setSubtitle.send(Protocol1_9To1_8.class);
+        }
+
+        final PacketWrapper setTitle = PacketWrapper.create(ClientboundPackets1_8.SET_TITLES, user);
+        setTitle.write(Types.VAR_INT, ACTION_SET_TITLE);
+        setTitle.write(Types.COMPONENT, title.title());
+        setTitle.send(Protocol1_9To1_8.class);
+
+        this.visible = false;
     }
 
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/data/CommandBlockState.java

@@ -0,0 +1,165 @@
+/*
+ * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
+ * Copyright (C) 2018-2026 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.viarewind.protocol.v1_9to1_8.data;
+
+import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.nbt.tag.NumberTag;
+import com.viaversion.nbt.tag.StringTag;
+
+public final class CommandBlockState {
+
+    public static final int COMMAND_BLOCK_COMMAND_LIMIT = 32500;
+
+    private static final String IMPULSE = "IMPULSE";
+    private static final String REPEAT = "REPEAT";
+    private static final String CHAIN = "CHAIN";
+    private static final String CONDITIONAL = "CONDITIONAL";
+    private static final String UNCONDITIONAL = "UNCONDITIONAL";
+    private static final String ALWAYS_ACTIVE = "ALWAYSACTIVE";
+    private static final String REDSTONE = "REDSTONE";
+
+    private CommandBlockState() {
+    }
+
+    public static boolean isCommandBlock(final int blockState) {
+        return isImpulse(blockState) || isRepeat(blockState) || isChain(blockState);
+    }
+
+    public static void decorateCommand(final CompoundTag tag, final int blockState) {
+        if (tag == null || !isCommandBlock(blockState)) {
+            return;
+        }
+
+        final StringTag commandTag = tag.getStringTag("Command");
+        if (commandTag == null) {
+            return;
+        }
+
+        final Mode mode = mode(blockState);
+        final boolean conditional = (blockState & 8) != 0;
+        final boolean automatic = booleanTag(tag, "auto");
+        if (mode == Mode.REDSTONE && !conditional && !automatic) {
+            return;
+        }
+
+        final String prefix = mode.prefix + ' ' + (conditional ? CONDITIONAL : UNCONDITIONAL) + ' ' + (automatic ? ALWAYS_ACTIVE : REDSTONE) + ' ';
+        final String command = commandTag.getValue();
+        if (!parseDecoratedCommand(command).prefixed() && prefix.length() + command.length() <= COMMAND_BLOCK_COMMAND_LIMIT) {
+            commandTag.setValue(prefix + command);
+        }
+    }
+
+    public static ParsedCommand parseDecoratedCommand(final String command) {
+        final int first = command.indexOf(' ');
+        if (first == -1) {
+            return ParsedCommand.defaultState(command);
+        }
+        final int second = command.indexOf(' ', first + 1);
+        if (second == -1) {
+            return ParsedCommand.defaultState(command);
+        }
+        final int third = command.indexOf(' ', second + 1);
+        if (third == -1) {
+            return ParsedCommand.defaultState(command);
+        }
+
+        final Mode mode = Mode.fromPrefix(command.substring(0, first));
+        if (mode == null) {
+            return ParsedCommand.defaultState(command);
+        }
+
+        final String conditionalToken = command.substring(first + 1, second);
+        final boolean conditional;
+        if (CONDITIONAL.equalsIgnoreCase(conditionalToken)) {
+            conditional = true;
+        } else if (UNCONDITIONAL.equalsIgnoreCase(conditionalToken)) {
+            conditional = false;
+        } else {
+            return ParsedCommand.defaultState(command);
+        }
+
+        final String automaticToken = command.substring(second + 1, third);
+        final boolean automatic;
+        if (ALWAYS_ACTIVE.equalsIgnoreCase(automaticToken)) {
+            automatic = true;
+        } else if (REDSTONE.equalsIgnoreCase(automaticToken)) {
+            automatic = false;
+        } else {
+            return ParsedCommand.defaultState(command);
+        }
+
+        return new ParsedCommand(command.substring(third + 1), mode.serverName, conditional, automatic, true);
+    }
+
+    private static boolean booleanTag(final CompoundTag tag, final String key) {
+        final NumberTag numberTag = tag.getNumberTag(key);
+        return numberTag != null && numberTag.asByte() != 0;
+    }
+
+    private static Mode mode(final int blockState) {
+        if (isRepeat(blockState)) {
+            return Mode.AUTO;
+        }
+        if (isChain(blockState)) {
+            return Mode.SEQUENCE;
+        }
+        return Mode.REDSTONE;
+    }
+
+    private static boolean isImpulse(final int blockState) {
+        return blockState >= 2192 && blockState <= 2207;
+    }
+
+    private static boolean isRepeat(final int blockState) {
+        return blockState >= 3360 && blockState <= 3375;
+    }
+
+    private static boolean isChain(final int blockState) {
+        return blockState >= 3376 && blockState <= 3391;
+    }
+
+    public record ParsedCommand(String command, String mode, boolean conditional, boolean automatic, boolean prefixed) {
+
+        private static ParsedCommand defaultState(final String command) {
+            return new ParsedCommand(command, Mode.REDSTONE.serverName, false, false, false);
+        }
+    }
+
+    private enum Mode {
+        REDSTONE(IMPULSE, "REDSTONE"),
+        AUTO(REPEAT, "AUTO"),
+        SEQUENCE(CHAIN, "SEQUENCE");
+
+        private final String prefix;
+        private final String serverName;
+
+        Mode(final String prefix, final String serverName) {
+            this.prefix = prefix;
+            this.serverName = serverName;
+        }
+
+        private static Mode fromPrefix(final String prefix) {
+            for (final Mode mode : values()) {
+                if (mode.prefix.equalsIgnoreCase(prefix)) {
+                    return mode;
+                }
+            }
+            return null;
+        }
+    }
+}

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/rewriter/BlockItemPacketRewriter1_9.java

@@ -19,6 +19,7 @@ package com.viaversion.viarewind.protocol.v1_9to1_8.rewriter;
 
 import com.viaversion.nbt.tag.ByteTag;
 import com.viaversion.nbt.tag.CompoundTag;
+import com.viaversion.nbt.tag.IntTag;
 import com.viaversion.nbt.tag.ListTag;
 import com.viaversion.nbt.tag.StringTag;
 import com.viaversion.nbt.tag.Tag;
@@ -26,8 +27,11 @@ import com.viaversion.viabackwards.api.rewriters.LegacyEnchantmentRewriter;
 import com.viaversion.viarewind.api.rewriter.VRBlockItemRewriter;
 import com.viaversion.viarewind.protocol.v1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viarewind.protocol.v1_9to1_8.data.PotionIdMappings1_8;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.CommandBlockStateStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.WindowTracker;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.BlockChangeRecord;
+import com.viaversion.viaversion.api.minecraft.BlockPosition;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
 import com.viaversion.viaversion.api.type.Types;
@@ -59,8 +63,26 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
 
     @Override
     protected void registerPackets() {
-        registerBlockChange(ClientboundPackets1_9.BLOCK_UPDATE);
-        registerMultiBlockChange(ClientboundPackets1_9.CHUNK_BLOCKS_UPDATE);
+        protocol.registerClientbound(ClientboundPackets1_9.BLOCK_UPDATE, wrapper -> {
+            final BlockPosition position = wrapper.passthrough(Types.BLOCK_POSITION1_8);
+            final int blockState = wrapper.passthrough(Types.VAR_INT);
+            wrapper.user().get(CommandBlockStateStorage.class).storeOrRemove(position, blockState);
+            wrapper.set(Types.VAR_INT, 0, handleBlockId(blockState));
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_9.CHUNK_BLOCKS_UPDATE, wrapper -> {
+            final int chunkX = wrapper.passthrough(Types.INT);
+            final int chunkZ = wrapper.passthrough(Types.INT);
+            final BlockChangeRecord[] records = wrapper.passthrough(Types.BLOCK_CHANGE_ARRAY);
+            final CommandBlockStateStorage storage = wrapper.user().get(CommandBlockStateStorage.class);
+
+            for (BlockChangeRecord record : records) {
+                final int blockState = record.getBlockId();
+                final BlockPosition position = new BlockPosition((chunkX << 4) + record.getSectionX(), record.getY(), (chunkZ << 4) + record.getSectionZ());
+                storage.storeOrRemove(position, blockState);
+                record.setBlockId(handleBlockId(blockState));
+            }
+        });
         registerSetCreativeModeSlot(ServerboundPackets1_8.SET_CREATIVE_MODE_SLOT);
 
         protocol.registerClientbound(ClientboundPackets1_9.CONTAINER_CLOSE, wrapper -> {
@@ -78,8 +100,12 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
         protocol.registerClientbound(ClientboundPackets1_9.OPEN_SCREEN, wrapper -> {
             final short windowId = wrapper.passthrough(Types.UNSIGNED_BYTE);
             final String windowType = wrapper.passthrough(Types.STRING);
+            wrapper.passthrough(Types.COMPONENT); // title
+            final short slotCount = wrapper.passthrough(Types.UNSIGNED_BYTE);
 
-            wrapper.user().get(WindowTracker.class).put(windowId, windowType);
+            final WindowTracker tracker = wrapper.user().get(WindowTracker.class);
+            tracker.put(windowId, windowType);
+            tracker.openWindow(windowId, windowType, slotCount);
         });
 
         protocol.registerClientbound(ClientboundPackets1_9.CONTAINER_SET_CONTENT, wrapper -> {
@@ -115,10 +141,49 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
             final Item item = wrapper.passthrough(Types.ITEM1_8);
 
             handleItemToClient(wrapper.user(), item);
+            if (windowId == -2) {
+                // 1.8 has no window -2 (set a player-inv slot by raw index, ignoring the open container) — retarget it.
+                final WindowTracker tracker = wrapper.user().get(WindowTracker.class);
+                final short openWindow = tracker.openWindowId();
+                if (openWindow != 0) {
+                    // Foreign container open: 1.8 only applies player-inv changes through it (main=size.., hotbar=size+27..).
+                    final int size = tracker.openWindowSize();
+                    final int containerSlot;
+                    if (slot >= 0 && slot <= 8) {
+                        containerSlot = size + 27 + slot;
+                    } else if (slot >= 9 && slot <= 35) {
+                        containerSlot = size + slot - 9;
+                    } else { // armor/offhand: no slot in a foreign container
+                        wrapper.cancel();
+                        return;
+                    }
+                    wrapper.set(Types.BYTE, 0, (byte) openWindow);
+                    wrapper.set(Types.SHORT, 0, (short) containerSlot);
+                    return;
+                }
+
+                // Otherwise window 0 with the menu slot.
+                final int windowSlot;
+                if (slot >= 0 && slot <= 8) {
+                    windowSlot = slot + 36;
+                } else if (slot >= 9 && slot <= 35) {
+                    windowSlot = slot;
+                } else if (slot >= 36 && slot <= 39) {
+                    windowSlot = 44 - slot;
+                } else { // offhand/body/saddle: no 1.8 equivalent
+                    wrapper.cancel();
+                    return;
+                }
+                wrapper.set(Types.BYTE, 0, (byte) 0);
+                wrapper.set(Types.SHORT, 0, (short) windowSlot);
+                return;
+            }
+
             if (windowId == 0 && slot == 45) {
                 wrapper.cancel();
                 return;
             }
+
             final WindowTracker windowTracker = wrapper.user().get(WindowTracker.class);
             final String windowType = windowTracker.get(windowId);
             if (windowType != null && windowType.equalsIgnoreCase("minecraft:brewing_stand")) {
@@ -194,6 +259,7 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
     @Override
     public Item handleItemToClient(UserConnection connection, Item item) {
         if (item == null) return null;
+        final int originalId = item.identifier();
         super.handleItemToClient(connection, item);
 
         CompoundTag tag = item.tag();
@@ -280,6 +346,32 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
             });
         }
 
+        // Colors the fake leather armor for an elytra gray
+        if (originalId == 443) {
+            if (tag == null) {
+                item.setTag(tag = new CompoundTag());
+            }
+            CompoundTag display = tag.getCompoundTag("display");
+            if (display == null) {
+                tag.put("display", display = new CompoundTag());
+            }
+            display.put("color", new IntTag(0x737373)); // Gray
+            tag.put(nbtTagName() + "|noDisplay", new ByteTag(true));
+        }
+
+        // Makes the fake banner for a shield brown if it has no banner patterns
+        if (originalId == 442) {
+            final CompoundTag blockEntityTag = tag == null ? null : tag.getCompoundTag("BlockEntityTag");
+            final ListTag<CompoundTag> patterns = blockEntityTag == null ? null : blockEntityTag.getListTag("Patterns", CompoundTag.class);
+            if (patterns == null || patterns.isEmpty()) {
+                item.setData((short) 3); // Brown
+                if (tag == null) {
+                    item.setTag(tag = new CompoundTag());
+                }
+                tag.put(nbtTagName() + "|noData", new ByteTag(true));
+            }
+        }
+
         return item;
     }
 
@@ -304,7 +396,8 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
             item.setData((short) 0);
         }
 
-        if (item.identifier() == 373 && (tag == null || !tag.contains("Potion"))) { // Potions
+        if (item.identifier() == 373) { // Potions
+            // Restore the splash id even when a Potion tag is present (e.g. items re-sent by a creative mode client)
             if (item.data() >= 16384) {
                 item.setIdentifier(438);
                 item.setData((short) (item.data() - 8192));
@@ -322,6 +415,9 @@ public class BlockItemPacketRewriter1_9 extends VRBlockItemRewriter<ClientboundP
         if (tag == null) {
             return item;
         }
+        if (tag.remove(nbtTagName() + "|noData") != null) {
+            item.setData((short) 0);
+        }
         final Tag noDisplayTag = tag.remove(nbtTagName() + "|noDisplay");
         if (noDisplayTag != null) {
             tag.remove("display");

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/rewriter/EntityPacketRewriter1_9.java

@@ -68,7 +68,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             final int dimension = wrapper.passthrough(Types.BYTE);
 
             trackPlayer(wrapper.user(), entityId);
-            final ClientWorld clientWorld = wrapper.user().getClientWorld(Protocol1_9To1_8.class);
+            final ClientWorld clientWorld = wrapper.user().storables(protocol).clientWorld();
             clientWorld.setEnvironment(dimension);
         });
         protocol.registerClientbound(ClientboundPackets1_9.SET_ENTITY_DATA, wrapper -> {
@@ -134,11 +134,24 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                         }
                     }
 
-                    if (data > 0) {
-                        wrapper.passthrough(Types.SHORT); // Velocity x
-                        wrapper.passthrough(Types.SHORT); // Velocity y
-                        wrapper.passthrough(Types.SHORT); // Velocity z
-                    } else {
+                    if (type.is(EntityTypes1_9.EntityType.POTION) && data > 0) {
+                        // 1.8 clients read the potion type from the object data, but newer versions only
+                        // send it in the entity data - the next packet. Held until then, see handleEntityData
+                        wrapper.cancel();
+                        final int x = wrapper.get(Types.INT, 0);
+                        final int y = wrapper.get(Types.INT, 1);
+                        final int z = wrapper.get(Types.INT, 2);
+                        final byte pitch = wrapper.get(Types.BYTE, 1);
+                        final byte yaw = wrapper.get(Types.BYTE, 2);
+                        final short velocityX = wrapper.passthrough(Types.SHORT);
+                        final short velocityY = wrapper.passthrough(Types.SHORT);
+                        final short velocityZ = wrapper.passthrough(Types.SHORT);
+                        final EntityTracker1_9 tracker = tracker(wrapper.user());
+                        tracker.getPendingPotions().put(entityId, new EntityTracker1_9.PendingPotionEntity(x, y, z, pitch, yaw, velocityX, velocityY, velocityZ));
+                        return;
+                    }
+
+                    if (data <= 0) {
                         final short velocityX = wrapper.read(Types.SHORT);
                         final short velocityY = wrapper.read(Types.SHORT);
                         final short velocityZ = wrapper.read(Types.SHORT);
@@ -164,7 +177,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                 map(Types.SHORT); // Count
                 handler(wrapper -> {
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
-                    wrapper.user().getEntityTracker(Protocol1_9To1_8.class).addEntity(entityId, EntityTypes1_9.EntityType.EXPERIENCE_ORB);
+                    wrapper.user().getEntityTracker(protocol).addEntity(entityId, EntityTypes1_9.EntityType.EXPERIENCE_ORB);
                 });
             }
         });
@@ -179,7 +192,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                 map(Types.DOUBLE, Protocol1_9To1_8.DOUBLE_TO_INT_TIMES_32); // Z
                 handler(wrapper -> {
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
-                    wrapper.user().getEntityTracker(Protocol1_9To1_8.class).addEntity(entityId, EntityTypes1_9.EntityType.LIGHTNING_BOLT);
+                    wrapper.user().getEntityTracker(protocol).addEntity(entityId, EntityTypes1_9.EntityType.LIGHTNING_BOLT);
                 });
             }
         });
@@ -216,7 +229,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                 map(Types.BYTE, Types.UNSIGNED_BYTE); // Direction
                 handler(wrapper -> {
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
-                    wrapper.user().getEntityTracker(Protocol1_9To1_8.class).addEntity(entityId, EntityTypes1_9.EntityType.PAINTING);
+                    wrapper.user().getEntityTracker(protocol).addEntity(entityId, EntityTypes1_9.EntityType.PAINTING);
                 });
             }
         });
@@ -259,7 +272,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             final int deltaY = wrapper.read(Types.SHORT);
             final int deltaZ = wrapper.read(Types.SHORT);
 
-            final Vector[] moves = RelativeMoveUtil.calculateRelativeMoves(wrapper.user(), entityId, deltaX, deltaY, deltaZ);
+            final Vector[] moves = RelativeMoveUtil.calculateRelativeMoves(tracker(wrapper.user()), entityId, deltaX, deltaY, deltaZ);
 
             wrapper.write(Types.BYTE, (byte) moves[0].blockX());
             wrapper.write(Types.BYTE, (byte) moves[0].blockY());
@@ -285,7 +298,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             final int deltaY = wrapper.read(Types.SHORT);
             final int deltaZ = wrapper.read(Types.SHORT);
 
-            final Vector[] moves = RelativeMoveUtil.calculateRelativeMoves(wrapper.user(), entityId, deltaX, deltaY, deltaZ);
+            final Vector[] moves = RelativeMoveUtil.calculateRelativeMoves(tracker(wrapper.user()), entityId, deltaX, deltaY, deltaZ);
 
             wrapper.write(Types.BYTE, (byte) moves[0].blockX());
             wrapper.write(Types.BYTE, (byte) moves[0].blockY());
@@ -295,7 +308,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             final byte pitch = wrapper.passthrough(Types.BYTE);
             final boolean onGround = wrapper.passthrough(Types.BOOLEAN);
 
-            com.viaversion.viaversion.api.minecraft.entities.EntityType type = wrapper.user().getEntityTracker(Protocol1_9To1_8.class).entityType(entityId);
+            com.viaversion.viaversion.api.minecraft.entities.EntityType type = wrapper.user().getEntityTracker(protocol).entityType(entityId);
             if (type == EntityTypes1_9.EntityType.BOAT) {
                 yaw -= 64;
                 wrapper.set(Types.BYTE, 3, yaw);
@@ -317,7 +330,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
 
         protocol.registerClientbound(ClientboundPackets1_9.MOVE_ENTITY_ROT, wrapper -> {
             final int entityId = wrapper.passthrough(Types.VAR_INT);
-            final com.viaversion.viaversion.api.minecraft.entities.EntityType type = wrapper.user().getEntityTracker(Protocol1_9To1_8.class).entityType(entityId);
+            final com.viaversion.viaversion.api.minecraft.entities.EntityType type = wrapper.user().getEntityTracker(protocol).entityType(entityId);
             if (type == EntityTypes1_9.EntityType.BOAT) {
                 byte yaw = wrapper.read(Types.BYTE);
                 yaw -= 64;
@@ -329,7 +342,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             @Override
             public void register() {
                 handler(wrapper -> {
-                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
                     final Integer vehicle = tracker.getVehicle(tracker.clientEntityId());
                     if (vehicle == null) {
                         wrapper.cancel();
@@ -360,7 +373,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                     }
 
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
-                    final EntityType type = wrapper.user().getEntityTracker(Protocol1_9To1_8.class).entityType(entityId);
+                    final EntityType type = wrapper.user().getEntityTracker(protocol).entityType(entityId);
                     if (type == EntityTypes1_9.EntityType.BOAT) {
                         byte yaw = wrapper.get(Types.BYTE, 0);
                         yaw -= 64;
@@ -379,7 +392,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             if (effectId > 23) { // Throw away new effects
                 wrapper.cancel();
             }
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             if (effectId == 25 && entityId == tracker.clientEntityId()) {
                 wrapper.user().get(LevitationStorage.class).setActive(false);
             }
@@ -416,7 +429,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
         protocol.registerClientbound(ClientboundPackets1_9.SET_PASSENGERS, null, wrapper -> {
             wrapper.cancel();
 
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             final int vehicle = wrapper.read(Types.VAR_INT);
             final IntList oldPassengers = tracker.getPassengers(vehicle);
 
@@ -444,6 +457,19 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             }
         });
 
+        protocol.registerClientbound(ClientboundPackets1_9.SET_ENTITY_MOTION, wrapper -> {
+            final int entityId = wrapper.passthrough(Types.VAR_INT);
+            final EntityTracker1_9 tracker = tracker(wrapper.user());
+            final EntityTracker1_9.PendingPotionEntity pending = tracker.getPendingPotions().get(entityId);
+            if (pending != null) {
+                wrapper.cancel();
+                final short velocityX = wrapper.read(Types.SHORT);
+                final short velocityY = wrapper.read(Types.SHORT);
+                final short velocityZ = wrapper.read(Types.SHORT);
+                tracker.getPendingPotions().put(entityId, pending.withVelocity(velocityX, velocityY, velocityZ));
+            }
+        });
+
         protocol.registerClientbound(ClientboundPackets1_9.TELEPORT_ENTITY, new PacketHandlers() {
             @Override
             public void register() {
@@ -457,7 +483,19 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                 handler(wrapper -> {
                     final int entityId = wrapper.get(Types.VAR_INT, 0);
 
-                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
+                    final EntityTracker1_9.PendingPotionEntity pending = tracker.getPendingPotions().get(entityId);
+                    if (pending != null) {
+                        wrapper.cancel();
+                        final int x = wrapper.get(Types.INT, 0);
+                        final int y = wrapper.get(Types.INT, 1);
+                        final int z = wrapper.get(Types.INT, 2);
+                        final byte yaw = wrapper.get(Types.BYTE, 0);
+                        final byte pitch = wrapper.get(Types.BYTE, 1);
+                        tracker.getPendingPotions().put(entityId, pending.withPosition(x, y, z, pitch, yaw));
+                        return;
+                    }
+
                     if (tracker.entityType(entityId) == EntityTypes1_9.EntityType.BOAT) {
                         byte yaw = wrapper.get(Types.BYTE, 0);
                         yaw -= 64;
@@ -475,7 +513,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
         protocol.registerClientbound(ClientboundPackets1_9.UPDATE_ATTRIBUTES, wrapper -> {
             final int entityId = wrapper.passthrough(Types.VAR_INT);
 
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             final boolean player = entityId == tracker.clientEntityId();
 
             // Throw away new attributes and track attack speed
@@ -522,7 +560,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             if (effectId > 23) { // Throw away new effects
                 wrapper.cancel();
             }
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             if (effectId == 25 && entityId == tracker.clientEntityId()) {
                 final LevitationStorage levitation = wrapper.user().get(LevitationStorage.class);
                 levitation.setActive(true);
@@ -541,10 +579,56 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
         filter().handler(this::handleEntityData);
     }
 
+    private void sendDelayedPotionSpawn(final EntityDataHandlerEvent event, final EntityTracker1_9 tracker, final Item item) {
+        final EntityTracker1_9.PendingPotionEntity spawn = tracker.getPendingPotions().remove(event.entityId());
+        if (spawn == null) {
+            return;
+        }
+
+        final Item converted = protocol.getItemRewriter().handleItemToClient(event.user(), item);
+        short data = converted == null ? 0 : converted.data();
+        if (data <= 0) {
+            data = 16384; // Unmapped potion, at least display a splash bottle
+        }
+
+        final PacketWrapper addEntity = PacketWrapper.create(ClientboundPackets1_8.ADD_ENTITY, event.user());
+        addEntity.write(Types.VAR_INT, event.entityId());
+        addEntity.write(Types.BYTE, (byte) EntityTypes1_9.ObjectType.POTION.getId());
+        addEntity.write(Types.INT, spawn.x());
+        addEntity.write(Types.INT, spawn.y());
+        addEntity.write(Types.INT, spawn.z());
+        addEntity.write(Types.BYTE, spawn.pitch());
+        addEntity.write(Types.BYTE, spawn.yaw());
+        addEntity.write(Types.INT, (int) data);
+        addEntity.write(Types.SHORT, spawn.velocityX());
+        addEntity.write(Types.SHORT, spawn.velocityY());
+        addEntity.write(Types.SHORT, spawn.velocityZ());
+        addEntity.send(Protocol1_9To1_8.class); // Before the entity data is sent
+
+        // 1.8 clients never apply a potion spawn's velocity - vanilla servers send it in a separate
+        // velocity packet after the spawn, so do the same
+        final PacketWrapper setEntityMotion = PacketWrapper.create(ClientboundPackets1_8.SET_ENTITY_MOTION, event.user());
+        setEntityMotion.write(Types.VAR_INT, event.entityId());
+        setEntityMotion.write(Types.SHORT, spawn.velocityX());
+        setEntityMotion.write(Types.SHORT, spawn.velocityY());
+        setEntityMotion.write(Types.SHORT, spawn.velocityZ());
+        setEntityMotion.send(Protocol1_9To1_8.class);
+    }
+
     private void handleEntityData(EntityDataHandlerEvent event, EntityData entityData) {
         final EntityTracker1_9 tracker = tracker(event.user());
+        if (event.entityType() == EntityTypes1_9.EntityType.POTION && entityData.value() instanceof Item potionItem) {
+            // No 1.8 equivalent; supplies the object data of the held-back spawn. Matched by value type as the index is version dependent
+            this.sendDelayedPotionSpawn(event, tracker, potionItem);
+            event.cancel();
+            return;
+        }
+
         if (entityData.id() == EntityDataIndex1_9.ENTITY_STATUS.getIndex()) {
             tracker.getStatus().put(event.entityId(), (Byte) entityData.value());
+            if (tracker.isHandActive(event.entityId())) {
+                entityData.setValue((byte) ((byte) entityData.value() | 1 << STATUS_USE_BIT));
+            }
         }
         final EntityDataIndex1_9 metaIndex = EntityDataIndex1_8.searchIndex(event.entityType(), entityData.id());
         if (metaIndex == null) {
@@ -554,8 +638,10 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
         }
         if (metaIndex.getOldType() == null || metaIndex.getNewType() == null) {
             if (metaIndex == EntityDataIndex1_9.PLAYER_HAND) { // Player eating/aiming/drinking
+                final boolean handActive = (((byte) entityData.value()) & 1 << HAND_ACTIVE_BIT) != 0;
+                tracker.setHandActive(event.entityId(), handActive);
                 byte status = (byte) tracker.getStatus().getOrDefault(event.entityId(), 0);
-                if ((((byte) entityData.value()) & 1 << HAND_ACTIVE_BIT) != 0) {
+                if (handActive) {
                     status = (byte) (status | 1 << STATUS_USE_BIT);
                 } else {
                     status = (byte) (status & ~(1 << STATUS_USE_BIT));

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/rewriter/PlayerPacketRewriter1_9.java

@@ -21,13 +21,14 @@ import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.ListTag;
 import com.viaversion.nbt.tag.StringTag;
 import com.viaversion.viarewind.ViaRewind;
-import com.viaversion.viarewind.api.type.RewindTypes;
 import com.viaversion.viarewind.protocol.v1_9to1_8.Protocol1_9To1_8;
+import com.viaversion.viarewind.protocol.v1_9to1_8.data.CommandBlockState;
 import com.viaversion.viarewind.protocol.v1_9to1_8.provider.InventoryProvider;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.BlockPlaceDestroyTracker;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.BossBarStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.CooldownStorage;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.EntityTracker1_9;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.LastTitle;
 import com.viaversion.viarewind.protocol.v1_9to1_8.storage.PlayerPositionTracker;
 import com.viaversion.viarewind.utils.ChatUtil;
 import com.viaversion.viaversion.api.Via;
@@ -43,7 +44,6 @@ import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
 import com.viaversion.viaversion.api.rewriter.RewriterBase;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.libs.gson.JsonElement;
-import com.viaversion.viaversion.libs.gson.JsonParser;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_8;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_9;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ServerboundPackets1_8;
@@ -53,6 +53,12 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 
+import static com.viaversion.viarewind.protocol.v1_9to1_8.cooldown.TitleCooldownVisualization.ACTION_HIDE;
+import static com.viaversion.viarewind.protocol.v1_9to1_8.cooldown.TitleCooldownVisualization.ACTION_RESET;
+import static com.viaversion.viarewind.protocol.v1_9to1_8.cooldown.TitleCooldownVisualization.ACTION_SET_SUBTITLE;
+import static com.viaversion.viarewind.protocol.v1_9to1_8.cooldown.TitleCooldownVisualization.ACTION_SET_TIMES_AND_DISPLAY;
+import static com.viaversion.viarewind.protocol.v1_9to1_8.cooldown.TitleCooldownVisualization.ACTION_SET_TITLE;
+
 public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
 
     public PlayerPacketRewriter1_9(Protocol1_9To1_8 protocol) {
@@ -107,6 +113,26 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
 
         protocol.cancelClientbound(ClientboundPackets1_9.COOLDOWN);
 
+        protocol.registerClientbound(ClientboundPackets1_9.SET_TITLES, wrapper -> {
+            final int action = wrapper.passthrough(Types.VAR_INT);
+            if (action == ACTION_SET_TITLE) {
+                final JsonElement title = wrapper.passthrough(Types.COMPONENT);
+                wrapper.user().get(LastTitle.class).setTitle(title);
+            } else if (action == ACTION_SET_SUBTITLE) {
+                final JsonElement subtitle = wrapper.passthrough(Types.COMPONENT);
+                wrapper.user().get(LastTitle.class).setSubtitle(subtitle);
+            } else if (action == ACTION_SET_TIMES_AND_DISPLAY) {
+                final int fadeIn = wrapper.passthrough(Types.INT);
+                final int stay = wrapper.passthrough(Types.INT);
+                final int fadeOut = wrapper.passthrough(Types.INT);
+                wrapper.user().get(LastTitle.class).setTimes(fadeIn, stay, fadeOut);
+            } else if (action == ACTION_HIDE) {
+                wrapper.user().get(LastTitle.class).hide();
+            } else if (action == ACTION_RESET) {
+                wrapper.user().get(LastTitle.class).reset();
+            }
+        });
+
         protocol.registerClientbound(ClientboundPackets1_9.CUSTOM_PAYLOAD, new PacketHandlers() {
             @Override
             public void register() {
@@ -133,8 +159,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 map(Types.BYTE); // Relative arguments
                 handler(wrapper -> {
                     final PlayerPositionTracker pos = wrapper.user().get(PlayerPositionTracker.class);
-
-                    pos.setConfirmId(wrapper.read(Types.VAR_INT));
+                    final int teleportId = wrapper.read(Types.VAR_INT);
 
                     byte flags = wrapper.get(Types.BYTE, 0);
                     double x = wrapper.get(Types.DOUBLE, 0);
@@ -143,7 +168,11 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                     float yaw = wrapper.get(Types.FLOAT, 0);
                     float pitch = wrapper.get(Types.FLOAT, 1);
 
-                    wrapper.set(Types.BYTE, 0, (byte) 0);
+                    // 1.8 supports the rotation-relative flags (0x08/0x10) natively, and resolving them here
+                    // would snap the camera to the tracked rotation, which lags the client's live look. Keep
+                    // them on the wire and only resolve the position bits (native 1.8 servers use zero-delta
+                    // rotation-relative teleports to leave the camera untouched).
+                    wrapper.set(Types.BYTE, 0, (byte) (flags & 0x18));
 
                     if (flags != 0) {
                         if ((flags & 0x01) != 0) {
@@ -159,18 +188,17 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                             wrapper.set(Types.DOUBLE, 2, z);
                         }
                         if ((flags & 0x08) != 0) {
-                            yaw += pos.getYaw();
-                            wrapper.set(Types.FLOAT, 0, yaw);
+                            yaw += pos.getYaw(); // tracked estimate only; the wire keeps the delta
                         }
                         if ((flags & 0x10) != 0) {
                             pitch += pos.getPitch();
-                            wrapper.set(Types.FLOAT, 1, pitch);
                         }
                     }
 
                     pos.setPos(x, y, z);
                     pos.setYaw(yaw);
                     pos.setPitch(pitch);
+                    pos.queueTeleport(teleportId, x, y, z, pos.getYaw(), pos.getPitch(), (flags & 0x18) != 0);
                 });
             }
         });
@@ -180,11 +208,11 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             public void register() {
                 map(Types.INT); // Dimension
                 handler(wrapper -> {
-                    final ClientWorld world = wrapper.user().getClientWorld(Protocol1_9To1_8.class);
+                    final ClientWorld world = wrapper.user().storables(protocol).clientWorld();
                     final int dimension = wrapper.get(Types.INT, 0);
 
                     if (world.setEnvironment(dimension)) {
-                        final EntityTracker tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                        final EntityTracker tracker = wrapper.user().getEntityTracker(protocol);
                         tracker.clearEntities();
                         wrapper.user().get(BossBarStorage.class).reset();
                     }
@@ -203,7 +231,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 return;
             }
 
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             final int entityId = wrapper.passthrough(Types.VAR_INT);
             wrapper.passthrough(Types.INT); // Killer id
 
@@ -273,7 +301,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 handler(wrapper -> {
                     wrapper.user().get(PlayerPositionTracker.class).sendAnimations();
 
-                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                    final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
                     if (tracker.isInsideVehicle(tracker.clientEntityId())) {
                         wrapper.cancel();
                     }
@@ -291,7 +319,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 handler(wrapper -> {
                     final PlayerPositionTracker storage = wrapper.user().get(PlayerPositionTracker.class);
                     storage.sendAnimations();
-                    if (storage.getConfirmId() != -1) {
+                    if (storage.hasPendingTeleports()) {
                         return;
                     }
 
@@ -311,7 +339,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 handler(wrapper -> {
                     final PlayerPositionTracker storage = wrapper.user().get(PlayerPositionTracker.class);
                     storage.sendAnimations();
-                    if (storage.getConfirmId() != -1) {
+                    if (storage.hasPendingTeleports()) {
                         return;
                     }
 
@@ -333,13 +361,26 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
 
             final PlayerPositionTracker storage = wrapper.user().get(PlayerPositionTracker.class);
             storage.sendAnimations();
-            if (storage.getConfirmId() != -1) {
-                if (storage.getPosX() == x && storage.getPosY() == y && storage.getPosZ() == z && storage.getYaw() == yaw && storage.getPitch() == pitch) {
+            final PlayerPositionTracker.PendingTeleport teleport = storage.peekTeleport();
+            if (teleport != null) {
+                // 1.7 uses resynced hitbox minY for y however this can have small floating point error due to the calculations it does to get there on teleport confirm
+                // This Y error gets propagated from 1.7 to 1.8 to 1.9 which causes teleport confirmation to not properly be detected
+                // This fixes it similarly to how anticheats detect teleports: https://github.com/GrimAnticheat/Grim/blob/67aa3a9483a9b2a6987d594092697b4104c781f0/common/src/main/java/ac/grim/grimac/manager/SetbackTeleportUtil.java#L315
+                boolean closeEnoughY = Math.abs(teleport.y() - y) <= 1e-7;
+                // A view-relative teleport keeps its rotation deltas on the wire, so the client applies them
+                // to its own live look and echoes that - match on position only and adopt the echoed rotation
+                final boolean rotationMatches = teleport.viewRelative() || (teleport.yaw() == yaw && teleport.pitch() == pitch);
+
+                if (teleport.x() == x && closeEnoughY && teleport.z() == z && rotationMatches) {
                     final PacketWrapper confirmTeleport = PacketWrapper.create(ServerboundPackets1_9.ACCEPT_TELEPORTATION, wrapper.user());
-                    confirmTeleport.write(Types.VAR_INT, storage.getConfirmId());
+                    confirmTeleport.write(Types.VAR_INT, teleport.id());
                     confirmTeleport.sendToServer(Protocol1_9To1_8.class);
 
-                    storage.setConfirmId(-1);
+                    if (teleport.viewRelative()) {
+                        storage.setYaw(yaw);
+                        storage.setPitch(pitch);
+                    }
+                    storage.confirmTeleport();
                 }
             } else {
                 storage.setPos(x, y, z);
@@ -430,7 +471,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             final float sideways = wrapper.passthrough(Types.FLOAT);
             final float forward = wrapper.passthrough(Types.FLOAT);
 
-            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+            final EntityTracker1_9 tracker = wrapper.user().getEntityTracker(protocol);
             final Integer vehicle = tracker.getVehicle(tracker.clientEntityId());
 
             if (vehicle != null && tracker.entityType(vehicle) == EntityTypes1_9.EntityType.BOAT) {
@@ -480,7 +521,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                     final short flags = wrapper.get(Types.UNSIGNED_BYTE, 0);
 
                     final PacketWrapper updateSkin = PacketWrapper.create(ClientboundPackets1_8.SET_ENTITY_DATA, wrapper.user());
-                    updateSkin.write(Types.VAR_INT, wrapper.user().getEntityTracker(Protocol1_9To1_8.class).clientEntityId());
+                    updateSkin.write(Types.VAR_INT, wrapper.user().getEntityTracker(protocol).clientEntityId());
 
                     final List<EntityData> entityData = new ArrayList<>();
                     entityData.add(new EntityData(10, EntityDataTypes1_8.BYTE, (byte) flags));
@@ -524,7 +565,39 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                             pageTag.setValue(ChatUtil.jsonToLegacy(value));
                         }
                     } else if (channel.equals("MC|AdvCdm")) {
-                        wrapper.set(Types.STRING, 0, "MC|AdvCmd");
+                        final byte type = wrapper.read(Types.BYTE);
+                        if (type == 0) {
+                            final int x = wrapper.read(Types.INT);
+                            final int y = wrapper.read(Types.INT);
+                            final int z = wrapper.read(Types.INT);
+                            final CommandBlockState.ParsedCommand command = CommandBlockState.parseDecoratedCommand(wrapper.read(Types.STRING));
+                            final boolean trackOutput = wrapper.read(Types.BOOLEAN);
+                            if (command.prefixed()) {
+                                wrapper.set(Types.STRING, 0, "MC|AutoCmd");
+                                wrapper.write(Types.INT, x);
+                                wrapper.write(Types.INT, y);
+                                wrapper.write(Types.INT, z);
+                                wrapper.write(Types.STRING, command.command());
+                                wrapper.write(Types.BOOLEAN, trackOutput);
+                                wrapper.write(Types.STRING, command.mode());
+                                wrapper.write(Types.BOOLEAN, command.conditional());
+                                wrapper.write(Types.BOOLEAN, command.automatic());
+                            } else {
+                                wrapper.set(Types.STRING, 0, "MC|AdvCmd");
+                                wrapper.write(Types.BYTE, type);
+                                wrapper.write(Types.INT, x);
+                                wrapper.write(Types.INT, y);
+                                wrapper.write(Types.INT, z);
+                                wrapper.write(Types.STRING, command.command());
+                                wrapper.write(Types.BOOLEAN, trackOutput);
+                            }
+                        } else {
+                            wrapper.set(Types.STRING, 0, "MC|AdvCmd");
+                            wrapper.write(Types.BYTE, type);
+                            wrapper.passthrough(Types.INT); // Entity id
+                            wrapper.passthrough(Types.STRING); // Command
+                            wrapper.passthrough(Types.BOOLEAN); // Track output
+                        }
                     }
                 });
             }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/rewriter/WorldPacketRewriter1_9.java

@@ -22,7 +22,9 @@ import com.viaversion.nbt.tag.StringTag;
 import com.viaversion.nbt.tag.Tag;
 import com.viaversion.viarewind.ViaRewind;
 import com.viaversion.viarewind.protocol.v1_9to1_8.Protocol1_9To1_8;
+import com.viaversion.viarewind.protocol.v1_9to1_8.data.CommandBlockState;
 import com.viaversion.viarewind.protocol.v1_9to1_8.data.EffectIdMappings1_8;
+import com.viaversion.viarewind.protocol.v1_9to1_8.storage.CommandBlockStateStorage;
 import com.viaversion.viaversion.api.minecraft.BlockPosition;
 import com.viaversion.viaversion.api.minecraft.Environment;
 import com.viaversion.viaversion.api.minecraft.chunks.BaseChunk;
@@ -57,6 +59,12 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 map(Types.NAMED_COMPOUND_TAG); // Tag
                 handler(wrapper -> {
                     final CompoundTag tag = wrapper.get(Types.NAMED_COMPOUND_TAG, 0);
+                    final short action = wrapper.get(Types.UNSIGNED_BYTE, 0);
+
+                    if (action == 2) {
+                        final BlockPosition position = wrapper.get(Types.BLOCK_POSITION1_8, 0);
+                        CommandBlockState.decorateCommand(tag, wrapper.user().get(CommandBlockStateStorage.class).state(position));
+                    }
 
                     if (tag.remove("SpawnData") instanceof CompoundTag spawnData) {
                         final Tag id = spawnData.remove("id");
@@ -92,9 +100,12 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                     String name = wrapper.get(Types.STRING, 0);
                     name = protocol.getMappingData().getMappedNamedSound(name);
                     if (name == null) {
-                        wrapper.cancel();
-                    } else {
+                        return;
+                    }
+                    if (!name.isEmpty()) {
                         wrapper.set(Types.STRING, 0, name);
+                    } else {
+                        wrapper.cancel();
                     }
                 });
                 read(Types.VAR_INT); // Sound category
@@ -110,10 +121,12 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             @Override
             public void register() {
                 handler(wrapper -> {
-                    final Environment environment = wrapper.user().getClientWorld(Protocol1_9To1_8.class).getEnvironment();
+                    final Environment environment = wrapper.user().storables(protocol).clientWorld().getEnvironment();
+                    final CommandBlockStateStorage commandBlockStates = wrapper.user().get(CommandBlockStateStorage.class);
 
                     final int chunkX = wrapper.read(Types.INT);
                     final int chunkZ = wrapper.read(Types.INT);
+                    commandBlockStates.unloadChunk(chunkX, chunkZ);
 
                     wrapper.write(ChunkType1_8.forEnvironment(environment), new BaseChunk(chunkX, chunkZ, true, false, 0, new ChunkSection[16], null, new ArrayList<>()));
                 });
@@ -124,9 +137,24 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             @Override
             public void register() {
                 handler(wrapper -> {
-                    final Environment environment = wrapper.user().getClientWorld(Protocol1_9To1_8.class).getEnvironment();
+                    final Environment environment = wrapper.user().storables(protocol).clientWorld().getEnvironment();
+                    final CommandBlockStateStorage commandBlockStates = wrapper.user().get(CommandBlockStateStorage.class);
 
                     Chunk chunk = wrapper.read(ChunkType1_9_1.forEnvironment(environment));
+                    final Chunk originalChunk = chunk;
+
+                    chunk.getBlockEntities().forEach(nbt -> {
+                        if (!nbt.contains("x") || !nbt.contains("y") || !nbt.contains("z")) {
+                            return;
+                        }
+
+                        final BlockPosition position = new BlockPosition((int) nbt.get("x").getValue(), (int) nbt.get("y").getValue(), (int) nbt.get("z").getValue());
+                        final int blockState = blockStateAt(originalChunk, position);
+                        if (CommandBlockState.isCommandBlock(blockState)) {
+                            commandBlockStates.storeOrRemove(position, blockState);
+                            CommandBlockState.decorateCommand(nbt, blockState);
+                        }
+                    });
 
                     for (ChunkSection section : chunk.getSections()) {
                         if (section == null) continue;
@@ -267,4 +295,18 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             }
         });
     }
+
+    private static int blockStateAt(final Chunk chunk, final BlockPosition position) {
+        final int sectionY = position.y() >> 4;
+        if (sectionY < 0 || sectionY >= chunk.getSections().length) {
+            return -1;
+        }
+
+        final ChunkSection section = chunk.getSections()[sectionY];
+        if (section == null) {
+            return -1;
+        }
+
+        return section.palette(PaletteType.BLOCKS).idAt(position.x() & 0xF, position.y() & 0xF, position.z() & 0xF);
+    }
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/storage/CommandBlockStateStorage.java

@@ -0,0 +1,52 @@
+/*
+ * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
+ * Copyright (C) 2018-2026 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.viarewind.protocol.v1_9to1_8.storage;
+
+import com.viaversion.viarewind.protocol.v1_9to1_8.data.CommandBlockState;
+import com.viaversion.viaversion.api.connection.StorableObject;
+import com.viaversion.viaversion.api.minecraft.BlockPosition;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+public final class CommandBlockStateStorage implements StorableObject {
+
+    private final Map<BlockPosition, Integer> commandBlockStates = new HashMap<>();
+
+    public void storeOrRemove(final BlockPosition position, final int blockState) {
+        if (CommandBlockState.isCommandBlock(blockState)) {
+            commandBlockStates.put(position, blockState);
+        } else {
+            commandBlockStates.remove(position);
+        }
+    }
+
+    public int state(final BlockPosition position) {
+        return commandBlockStates.getOrDefault(position, -1);
+    }
+
+    public void unloadChunk(final int chunkX, final int chunkZ) {
+        final Iterator<BlockPosition> iterator = commandBlockStates.keySet().iterator();
+        while (iterator.hasNext()) {
+            final BlockPosition position = iterator.next();
+            if (position.x() >> 4 == chunkX && position.z() >> 4 == chunkZ) {
+                iterator.remove();
+            }
+        }
+    }
+}

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/storage/EntityTracker1_9.java

@@ -18,6 +18,7 @@
 package com.viaversion.viarewind.protocol.v1_9to1_8.storage;
 
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.entity.TrackedEntity;
 import com.viaversion.viaversion.api.minecraft.Vector;
 import com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_9;
 import com.viaversion.viaversion.data.entity.EntityTrackerBase;
@@ -27,6 +28,8 @@ import com.viaversion.viaversion.libs.fastutil.ints.Int2ObjectMap;
 import com.viaversion.viaversion.libs.fastutil.ints.Int2ObjectOpenHashMap;
 import com.viaversion.viaversion.libs.fastutil.ints.IntArrayList;
 import com.viaversion.viaversion.libs.fastutil.ints.IntList;
+import com.viaversion.viaversion.libs.fastutil.ints.IntOpenHashSet;
+import com.viaversion.viaversion.libs.fastutil.ints.IntSet;
 import java.util.List;
 import java.util.Map;
 
@@ -35,20 +38,24 @@ public class EntityTracker1_9 extends EntityTrackerBase {
     private final Int2ObjectMap<IntList> vehicles = new Int2ObjectOpenHashMap<>();
     private final Int2ObjectMap<Vector> offsets = new Int2ObjectOpenHashMap<>();
     private final Int2IntMap status = new Int2IntOpenHashMap();
+    private final IntSet handActive = new IntOpenHashSet();
+    private final Int2ObjectMap<PendingPotionEntity> pendingPotions = new Int2ObjectOpenHashMap<>();
 
     public EntityTracker1_9(UserConnection connection) {
         super(connection, EntityTypes1_9.EntityType.PLAYER);
     }
 
     @Override
-    public void removeEntity(int id) {
+    public TrackedEntity removeEntity(int id) {
         vehicles.remove(id);
         offsets.remove(id);
         status.remove(id);
+        handActive.remove(id);
+        pendingPotions.remove(id);
 
         vehicles.forEach((vehicle, passengers) -> passengers.rem(id));
         vehicles.int2ObjectEntrySet().removeIf(entry -> entry.getValue().isEmpty());
-        super.removeEntity(id);
+        return super.removeEntity(id);
     }
 
     public void resetEntityOffset(final int id) {
@@ -88,4 +95,33 @@ public class EntityTracker1_9 extends EntityTrackerBase {
     public Int2IntMap getStatus() {
         return status;
     }
+
+    public boolean isHandActive(final int id) {
+        return handActive.contains(id);
+    }
+
+    public void setHandActive(final int id, final boolean active) {
+        if (active) {
+            handActive.add(id);
+        } else {
+            handActive.remove(id);
+        }
+    }
+
+    public Int2ObjectMap<PendingPotionEntity> getPendingPotions() {
+        return pendingPotions;
+    }
+
+    public record PendingPotionEntity(int x, int y, int z, byte pitch, byte yaw, short velocityX, short velocityY, short velocityZ) {
+
+        public PendingPotionEntity withPosition(final int x, final int y, final int z, final byte pitch, final byte yaw) {
+            return new PendingPotionEntity(x, y, z, pitch, yaw, velocityX, velocityY, velocityZ);
+        }
+
+        public PendingPotionEntity withVelocity(final short velocityX, final short velocityY, final short velocityZ) {
+            return new PendingPotionEntity(x, y, z, pitch, yaw, velocityX, velocityY, velocityZ);
+        }
+
+    }
+
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/storage/LastTitle.java

@@ -0,0 +1,107 @@
+/*
+ * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
+ * Copyright (C) 2018-2026 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.viarewind.protocol.v1_9to1_8.storage;
+
+import com.viaversion.viaversion.api.connection.StorableObject;
+import com.viaversion.viaversion.libs.gson.JsonElement;
+
+public final class LastTitle implements StorableObject {
+
+    private JsonElement title;
+    private JsonElement subtitle;
+
+    private long visibleSince;
+    private long visibleUntil;
+
+    private int fadeIn;
+    private int stay;
+    private int fadeOut;
+
+    public LastTitle() {
+        this.reset();
+    }
+
+    public void setTitle(final JsonElement title) {
+        this.title = title;
+
+        final long now = System.currentTimeMillis();
+        this.visibleSince = now;
+        this.visibleUntil = now + titleLength();
+    }
+
+    public void setSubtitle(final JsonElement subtitle) {
+        this.subtitle = subtitle;
+    }
+
+    public void setTimes(final int fadeIn, final int stay, final int fadeOut) {
+        this.fadeIn = fadeIn;
+        this.stay = stay;
+        this.fadeOut = fadeOut;
+
+        if (this.visibleUntil > System.currentTimeMillis()) {
+            final long now = System.currentTimeMillis();
+            this.visibleSince = now;
+            this.visibleUntil = now + titleLength();
+        }
+    }
+
+    public void hide() {
+        this.visibleSince = 0;
+        this.visibleUntil = 0;
+    }
+
+    public void reset() {
+        this.hide();
+
+        this.fadeIn = 10;
+        this.stay = 70;
+        this.fadeOut = 20;
+    }
+
+    public boolean isVisible() {
+        return this.title != null && this.visibleUntil > System.currentTimeMillis();
+    }
+
+    public JsonElement title() {
+        return this.title;
+    }
+
+    public JsonElement subtitle() {
+        return this.subtitle;
+    }
+
+    public int[] remainingTimes() {
+        final int fullLength = Math.max(0, this.fadeIn + this.stay + this.fadeOut);
+        final int elapsed = (int) Math.min(fullLength, Math.max(0, (System.currentTimeMillis() - this.visibleSince) / 50L));
+        if (elapsed < this.fadeIn) {
+            return new int[]{this.fadeIn - elapsed, this.stay, this.fadeOut};
+        }
+
+        final int titleEnd = this.fadeIn + this.stay;
+        if (elapsed < titleEnd) {
+            return new int[]{0, titleEnd - elapsed, this.fadeOut};
+        }
+
+        return new int[]{0, 0, fullLength - elapsed};
+    }
+
+    private long titleLength() {
+        return Math.max(0, this.fadeIn + this.stay + this.fadeOut) * 50L;
+    }
+
+}

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/storage/PlayerPositionTracker.java

@@ -26,10 +26,10 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 public class PlayerPositionTracker implements StorableObject {
 
     private final Queue<PacketWrapper> animations = new ConcurrentLinkedQueue<>();
+    private final Queue<PendingTeleport> pendingTeleports = new ConcurrentLinkedQueue<>();
     private double posX, posY, posZ;
     private float yaw, pitch;
     private boolean onGround;
-    private int confirmId = -1;
 
     public void setPos(double x, double y, double z) {
         this.posX = x;
@@ -84,12 +84,23 @@ public class PlayerPositionTracker implements StorableObject {
         this.onGround = onGround;
     }
 
-    public int getConfirmId() {
-        return this.confirmId;
+    public boolean hasPendingTeleports() {
+        return !this.pendingTeleports.isEmpty();
     }
 
-    public void setConfirmId(int confirmId) {
-        this.confirmId = confirmId;
+    public void queueTeleport(final int id, final double x, final double y, final double z, final float yaw, final float pitch, final boolean viewRelative) {
+        this.pendingTeleports.add(new PendingTeleport(id, x, y, z, yaw, pitch, viewRelative));
+    }
+
+    public PendingTeleport peekTeleport() {
+        return this.pendingTeleports.peek();
+    }
+
+    public void confirmTeleport() {
+        this.pendingTeleports.poll();
+    }
+
+    public record PendingTeleport(int id, double x, double y, double z, float yaw, float pitch, boolean viewRelative) {
     }
 
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/storage/WindowTracker.java

@@ -38,6 +38,9 @@ public class WindowTracker extends StoredObject {
     private final HashMap<Short, Item[]> brewingItems = new HashMap<>();
     private final Map<Short, Short> enchantmentProperties = new HashMap<>();
 
+    private short openWindowId = 0;
+    private int openWindowSize = 0; // Translated client container slots, excluding the player inventory
+
     public WindowTracker(UserConnection user) {
         super(user);
     }
@@ -52,11 +55,11 @@ public class WindowTracker extends StoredObject {
         openWindow.write(Types.UNSIGNED_BYTE, windowId);
         openWindow.write(Types.STRING, "minecraft:brewing_stand");
 
-        TextComponent title = new StringComponent().
-            append(new TranslationComponent("container.brewing")).
-            append(new StringComponent(": " + TextFormatting.DARK_GRAY)).
-            append(new StringComponent(amount + " " + TextFormatting.DARK_RED)).
-            append(new TranslationComponent("item.blazePowder.name", TextFormatting.DARK_RED));
+        TextComponent title = new StringComponent()
+            .append(new TranslationComponent("container.brewing"))
+            .append(new StringComponent(": ").formatted(TextFormatting.DARK_GRAY))
+            .append(new StringComponent(amount + " ").formatted(TextFormatting.DARK_RED))
+            .append(new TranslationComponent("item.blazePowder.name").formatted(TextFormatting.DARK_RED));
 
         openWindow.write(Types.COMPONENT, TextComponentSerializer.V1_8.serializeJson(title));
         openWindow.write(Types.UNSIGNED_BYTE, (short) 420);
@@ -83,6 +86,36 @@ public class WindowTracker extends StoredObject {
     public void remove(short windowId) {
         types.remove(windowId);
         brewingItems.remove(windowId);
+        if (windowId == openWindowId) {
+            openWindowId = 0;
+            openWindowSize = 0;
+        }
+    }
+
+    public void openWindow(final short windowId, final String windowType, final int slotCount) {
+        openWindowId = windowId;
+
+        // The client only uses the packet's slot count when constructing dynamic inventories.
+        // Fixed menus construct their own slots; use the translated 1.8 layout for those.
+        openWindowSize = switch (windowType) {
+            case "minecraft:furnace", "minecraft:villager", "minecraft:anvil" -> 3;
+            case "minecraft:brewing_stand" -> 4;
+            case "minecraft:beacon" -> 1;
+            case "minecraft:dispenser", "minecraft:dropper" -> 9;
+            case "minecraft:enchanting_table" -> 2;
+            case "minecraft:crafting_table" -> 10;
+            case "minecraft:hopper" -> slotCount;
+            case "EntityHorse" -> slotCount > 2 ? 17 : 2;
+            default -> slotCount / 9 * 9;
+        };
+    }
+
+    public short openWindowId() {
+        return openWindowId;
+    }
+
+    public int openWindowSize() {
+        return openWindowSize;
     }
 
     public Item[] getBrewingItems(short windowId) {

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/task/CooldownIndicatorTask.java

@@ -26,7 +26,11 @@ public class CooldownIndicatorTask implements Runnable {
     @Override
     public void run() {
         for (UserConnection connection : Via.getManager().getConnectionManager().getConnections()) {
-            connection.get(CooldownStorage.class).tick(connection);
+            final CooldownStorage cooldown = connection.get(CooldownStorage.class);
+            if (cooldown == null) {
+                continue;
+            }
+            cooldown.tick(connection);
         }
     }
 }

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/task/LevitationUpdateTask.java

@@ -36,12 +36,15 @@ public class LevitationUpdateTask implements Runnable {
         }
         for (UserConnection connection : Via.getManager().getConnectionManager().getConnections()) {
             final LevitationStorage levitation = connection.get(LevitationStorage.class);
+            if (levitation == null) {
+                continue;
+            }
             if (!levitation.isActive()) {
                 continue;
             }
 
             final PacketWrapper velocityPacket = PacketWrapper.create(ClientboundPackets1_8.SET_ENTITY_MOTION, connection);
-            velocityPacket.write(Types.VAR_INT, connection.getEntityTracker(Protocol1_9To1_8.class).clientEntityId());
+            velocityPacket.write(Types.VAR_INT, connection.storables(Protocol1_9To1_8.class).entityTracker().clientEntityId());
             velocityPacket.write(Types.SHORT, (short) 0);
             velocityPacket.write(Types.SHORT, (short) ((levitation.getAmplifier() + 1) * 360));
             velocityPacket.write(Types.SHORT, (short) 0);

fabric/src/main/resources/fabric.mod.json

@@ -24,7 +24,7 @@
   },
   "depends": {
     "viafabric": ">=0.4.14",
-    "viabackwards": ">=5.7.2"
+    "viabackwards": ">=5.12.0"
   },
   "custom": {
     "modmenu:api": true,

gradle.properties

@@ -4,17 +4,18 @@ org.gradle.parallel=true
 org.gradle.configuration-cache=true
 
 # Project Details
-project_jvm_version=17
+jvm_version=17
 
 project_group=com.viaversion
-project_version=4.1.0
+project_name=ViaRewind
+project_version=4.2.0
 project_description=ViaVersion addon to allow 1.8.x and 1.7.x clients on newer server versions.
 
-publishing_dev_id=florianreuth
-publishing_dev_name=Florian Reuth
-publishing_dev_mail=git@florianreuth.de
+publish_owner_id=florianreuth
+publish_owner_name=Florian Reuth
+publish_owner_mail=git@florianreuth.de
 
 # Modrinth/Hangar Publishing
-minecraft_versions=26.1.2, 26.1.1, 26.1, 1.21.11, 1.21.10, 1.21.9, 1.21.8, 1.21.7, 1.21.6, 1.21.5, 1.21.4, 1.21.3, 1.21.2, 1.21.1, 1.21, 1.20.6, 1.20.5, 1.20.4, 1.20.3, 1.20.2, 1.20.1, 1.20, 1.19.4, 1.19.3, 1.19.2, 1.19.1, 1.19, 1.18.2, 1.18.1, 1.18, 1.17.1, 1.17, 1.16.5, 1.16.4, 1.16.3, 1.16.2, 1.16.1, 1.16, 1.15.2, 1.15.1, 1.15, 1.14.4, 1.14.3, 1.14.2, 1.14.1, 1.14, 1.13.2, 1.13.1, 1.13, 1.12.2, 1.12.1, 1.12, 1.11.2, 1.11.1, 1.11, 1.10.2, 1.10.1, 1.10, 1.9.4, 1.9.3, 1.9.2, 1.9.1, 1.9, 1.8.9, 1.8.8
-minecraft_version_range=1.8-26.1.2
+minecraft_versions=26.3, 26.2, 26.1.2, 26.1.1, 26.1, 1.21.11, 1.21.10, 1.21.9, 1.21.8, 1.21.7, 1.21.6, 1.21.5, 1.21.4, 1.21.3, 1.21.2, 1.21.1, 1.21, 1.20.6, 1.20.5, 1.20.4, 1.20.3, 1.20.2, 1.20.1, 1.20, 1.19.4, 1.19.3, 1.19.2, 1.19.1, 1.19, 1.18.2, 1.18.1, 1.18, 1.17.1, 1.17, 1.16.5, 1.16.4, 1.16.3, 1.16.2, 1.16.1, 1.16, 1.15.2, 1.15.1, 1.15, 1.14.4, 1.14.3, 1.14.2, 1.14.1, 1.14, 1.13.2, 1.13.1, 1.13, 1.12.2, 1.12.1, 1.12, 1.11.2, 1.11.1, 1.11, 1.10.2, 1.10.1, 1.10, 1.9.4, 1.9.3, 1.9.2, 1.9.1, 1.9, 1.8.9, 1.8.8
+minecraft_version_range=1.8-26.3
 velocity_version=3.4-3.5

gradle/wrapper/gradle-wrapper.properties

@@ -1,8 +1,10 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionSha256Sum=2ab2958f2a1e51120c326cad6f385153bb11ee93b3c216c5fccebfdfbb7ec6cb
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+distributionSha256Sum=acd53f1edaf02f1a8ff99879f8a34b302661a057d9b063ae9e35b552f804d20a
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.1-bin.zip
 networkTimeout=10000
+retries=0
+retryBackOffMs=500
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -20,7 +20,7 @@
 
 ##############################################################################
 #
-#   Gradle start up script for POSIX generated by Gradle.
+#   gradlew start up script for POSIX generated by Gradle.
 #
 #   Important for running:
 #
@@ -29,7 +29,7 @@
 #       bash, then to run this script, type that shell name before the whole
 #       command line, like:
 #
-#           ksh Gradle
+#           ksh gradlew
 #
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:
@@ -57,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/2d6327017519d23b96af35865dc997fcb544fb40/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.

gradlew.bat

@@ -19,12 +19,12 @@
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
-@rem  Gradle startup script for Windows
+@rem  gradlew startup script for Windows
 @rem
 @rem ##########################################################################
 
-@rem Set local scope for the variables with windows NT shell
-if "%OS%"=="Windows_NT" setlocal
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
 
 set DIRNAME=%~dp0
 if "%DIRNAME%"=="" set DIRNAME=.
@@ -51,7 +51,7 @@ echo. 1>&2
 echo Please set the JAVA_HOME variable in your environment to match the 1>&2
 echo location of your Java installation. 1>&2
 
-goto fail
+"%COMSPEC%" /c exit 1
 
 :findJavaFromJavaHome
 set JAVA_HOME=%JAVA_HOME:"=%
@@ -65,29 +65,18 @@ echo. 1>&2
 echo Please set the JAVA_HOME variable in your environment to match the 1>&2
 echo location of your Java installation. 1>&2
 
-goto fail
+"%COMSPEC%" /c exit 1
 
 :execute
 @rem Setup the command line
 
 
 
-@rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+@rem Execute gradlew
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
 
-:end
-@rem End local scope for the variables with windows NT shell
-if %ERRORLEVEL% equ 0 goto mainEnd
-
-:fail
-rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
-rem the _cmd.exe /c_ return code!
-set EXIT_CODE=%ERRORLEVEL%
-if %EXIT_CODE% equ 0 set EXIT_CODE=1
-if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
-exit /b %EXIT_CODE%
-
-:mainEnd
-if "%OS%"=="Windows_NT" endlocal
-
-:omega
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

settings.gradle.kts

@@ -6,7 +6,7 @@ pluginManagement {
     }
 
     plugins {
-        id("de.florianreuth.baseproject") version "2.0.2"
+        id("de.florianreuth.baseproject") version "3.0.2"
         id("io.papermc.hangar-publish-plugin") version "0.1.4"
         id("net.raphimc.class-token-replacer") version "1.1.7"
         id("com.modrinth.minotaur") version "2.+"

sponge/src/main/resources/META-INF/sponge_plugins.json

@@ -36,11 +36,11 @@
       },
       {
         "id": "viaversion",
-        "version": "[5.7.2,)"
+        "version": "[5.12.0,)"
       },
       {
         "id": "viabackwards",
-        "version": "[5.7.2,)"
+        "version": "[5.12.0,)"
       }
     ]
   },