Cancel own-player equipment packets in 1.9->1.8 (#733)

Needed since https://github.com/ViaVersion/ViaBackwards/commit/53105e644d005c37aaad7a31d1e9a78016026050 emulates SET_EQUIPMENT packets for the client player.

Co-authored-by: Kyllian Warmerdam <kyllian@Mac.localdomain>

.github/FUNDING.yml

@@ -1,2 +1,2 @@
-github: FlorianMichael
-custom: [ 'https://florianmichael.de/donate', 'https://creeper123123321.github.io/#donate' ]
+github: florianreuth
+custom: [ 'https://florianreuth.de/donate', 'https://creeper123123321.github.io/#donate' ]

.github/dependabot.yml

@@ -1,10 +1,22 @@
 version: 2
 updates:
   - package-ecosystem: "gradle"
+    cooldown:
+      default-days: 7
     directory: "/"
     schedule:
-      interval: "daily"
+      interval: "monthly"
+    groups:
+      all-dependencies:
+        patterns:
+          - "*"
   - package-ecosystem: "github-actions"
+    cooldown:
+      default-days: 7
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"
+    groups:
+      all-dependencies:
+        patterns:
+          - "*"

.github/workflows/build.yml

@@ -1,21 +1,32 @@
 name: Build
-on: [ pull_request, push, workflow_dispatch ]
-
+on: [pull_request, push, workflow_dispatch]
+permissions:
+  contents: read
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-26.04
+    timeout-minutes: 30
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
-      - name: Set up JDK 17
-        uses: actions/setup-java@v5
+        uses: gradle/actions/setup-gradle@9c971963bec38e04b3d30dcc455b5382be2fdbfb # v6.3.0
+        with:
+          cache-disabled: true
+          cache-provider: basic
+      - name: Set up Java
+        uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         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 # v7.0.1
+        with:
+          name: Artifacts
+          path: build/libs/
+          if-no-files-found: error

.github/workflows/publish.yml

@@ -4,26 +4,34 @@ on:
     branches:
       - master
       - dev
+  workflow_dispatch:
+
+permissions:
+  contents: read
 
 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@v5
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
-      - name: Set up JDK 17
-        uses: actions/setup-java@v5
+        uses: gradle/actions/setup-gradle@9c971963bec38e04b3d30dcc455b5382be2fdbfb # v6.3.0
+        with:
+          cache-disabled: true
+          cache-provider: basic
+      - name: Set up Java
+        uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 25
           check-latest: true
-      - name: Build
-        run: ./gradlew build
+      - name: Build with Gradle
+        run: ./gradlew build --stacktrace
       - name: Publish to Hangar
         env:
           HANGAR_TOKEN: ${{ secrets.HANGAR_TOKEN }}

build-logic/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    `kotlin-dsl`
+}
+
+dependencies {
+    implementation(libs.foojay.resolver.convention.plugin)
+    implementation(libs.classtokenreplacer.plugin)
+}

build-logic/settings.gradle.kts

@@ -0,0 +1,10 @@
+dependencyResolutionManagement {
+    repositories {
+        gradlePluginPortal()
+    }
+    versionCatalogs {
+        create("libs") {
+            from(files("../gradle/libs.versions.toml"))
+        }
+    }
+}

build-logic/src/main/kotlin/base.java.gradle.kts

@@ -0,0 +1,39 @@
+plugins {
+    `java-library`
+}
+
+group = property("project_group") as String
+version = property("project_version") as String
+description = property("project_description") as String
+
+if (project == rootProject) {
+    (findProperty("project_name") as String?)?.let { base.archivesName = it }
+}
+
+// The Kotlin plugin picks up the Java toolchain, so no Kotlin specific configuration is needed
+val jvmVersion = (property("jvm_version") as String).toInt()
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(jvmVersion)
+    sourceCompatibility = JavaVersion.toVersion(jvmVersion)
+    targetCompatibility = JavaVersion.toVersion(jvmVersion)
+}
+
+tasks.withType<JavaCompile>().configureEach {
+    options.encoding = "UTF-8"
+    options.compilerArgs.addAll(listOf("-nowarn", "-Xlint:-unchecked", "-Xlint:-deprecation"))
+}
+
+tasks.withType<Javadoc>().configureEach {
+    options.encoding = "UTF-8"
+    (options as StandardJavadocDocletOptions).apply {
+        addBooleanOption("Xdoclint:none", true)
+        quiet()
+    }
+}
+
+tasks.jar {
+    val projectName = project.name
+    from("LICENSE") {
+        rename { "LICENSE_$projectName" }
+    }
+}

build-logic/src/main/kotlin/base.maven_publish.gradle.kts

@@ -0,0 +1,60 @@
+plugins {
+    `java-library`
+    `maven-publish`
+    signing
+}
+
+val projectName = property("project_name") as String
+val ownerId = property("publish_owner_id") as String
+val ownerName = property("publish_owner_name") as String
+val ownerMail = property("publish_owner_mail") as String
+val githubAccount = findProperty("publish_github_account") as String? ?: ownerId
+val licenseName = findProperty("publish_license") as String? ?: "Apache-2.0"
+val githubRepository = "github.com/$githubAccount/$projectName"
+
+java {
+    withSourcesJar()
+    withJavadocJar()
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("maven") {
+            groupId = project.group.toString()
+            artifactId = project.name
+            version = project.version.toString()
+
+            from(components["java"])
+
+            pom {
+                name = projectName
+                // Lazy so that a description set in the build script body is picked up
+                description = provider { project.description }
+                url = "https://$githubRepository"
+                licenses {
+                    license {
+                        name = licenseName
+                        url = "https://$githubRepository/blob/main/LICENSE"
+                    }
+                }
+                developers {
+                    developer {
+                        id = ownerId
+                        name = ownerName
+                        email = ownerMail
+                    }
+                }
+                scm {
+                    connection = "scm:git:git://$githubRepository.git"
+                    developerConnection = "scm:git:ssh://$githubRepository.git"
+                    url = "https://$githubRepository"
+                }
+            }
+        }
+    }
+}
+
+signing {
+    isRequired = false
+    sign(publishing.publications)
+}

build-logic/src/main/kotlin/base.settings.settings.gradle.kts

@@ -0,0 +1,14 @@
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention")
+}
+
+enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS")
+
+dependencyResolutionManagement {
+    // Repositories live in the settings only, a project or plugin declaring its own fails the build
+    repositoriesMode = RepositoriesMode.FAIL_ON_PROJECT_REPOS
+    repositories {
+        mavenCentral()
+        maven("https://maven.florianreuth.de/releases")
+    }
+}

build-logic/src/main/kotlin/configuration.embedded_dependencies.gradle.kts

@@ -0,0 +1,16 @@
+plugins {
+    java
+}
+
+val embeddedDependencies = configurations.create("embeddedDependencies") {
+    isCanBeResolved = true
+    isCanBeConsumed = true
+}
+
+tasks.jar {
+    dependsOn(embeddedDependencies)
+    from({ embeddedDependencies.map { zipTree(it) } }) {
+        exclude("META-INF/*.RSA", "META-INF/*.SF", "META-INF/*.DSA")
+    }
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}

build-logic/src/main/kotlin/de/florianreuth/baseproject/Git.kt

@@ -0,0 +1,59 @@
+package de.florianreuth.baseproject
+
+import org.gradle.api.Project
+import org.gradle.api.provider.ListProperty
+import org.gradle.api.provider.ValueSource
+import org.gradle.api.provider.ValueSourceParameters
+import org.gradle.process.ExecOperations
+import java.io.ByteArrayOutputStream
+import javax.inject.Inject
+
+/**
+ * Short hash of the latest commit, or "unknown" if Git is unavailable.
+ */
+fun Project.latestCommitHash(): String = runGitCommand(listOf("rev-parse", "--short", "HEAD"))
+
+/**
+ * Message of the latest commit, or "unknown" if Git is unavailable.
+ */
+fun Project.latestCommitMessage(): String = runGitCommand(listOf("log", "-1", "--pretty=%B"))
+
+/**
+ * Name of the current branch, or "unknown" if Git is unavailable.
+ */
+fun Project.branchName(): String = runGitCommand(listOf("rev-parse", "--abbrev-ref", "HEAD"))
+
+/**
+ * Runs a Git command through a configuration-cache compatible [ValueSource].
+ *
+ * @param args the arguments passed to `git`
+ * @return the trimmed output, or "unknown" if the command fails or prints nothing
+ */
+fun Project.runGitCommand(args: List<String>): String {
+    return providers.of(GitCommand::class.java) { parameters.args.set(args) }.getOrNull() ?: "unknown"
+}
+
+abstract class GitCommand : ValueSource<String, GitCommand.GitCommandParameters> {
+
+    @get:Inject
+    abstract val execOperations: ExecOperations
+
+    interface GitCommandParameters : ValueSourceParameters {
+        val args: ListProperty<String>
+    }
+
+    override fun obtain(): String? {
+        try {
+            val output = ByteArrayOutputStream()
+            execOperations.exec {
+                commandLine = listOf("git") + parameters.args.get()
+                standardOutput = output
+                isIgnoreExitValue = true
+            }
+
+            return output.toString(Charsets.UTF_8).trim().takeIf { it.isNotBlank() }
+        } catch (_: Exception) {
+            return null
+        }
+    }
+}

build-logic/src/main/kotlin/de/florianreuth/baseproject/Via.kt

@@ -0,0 +1,78 @@
+/*
+ * This file is part of BaseProject - https://github.com/florianreuth/BaseProject
+ * Copyright (C) 2024-2026 Florian Reuth <git@florianreuth.de>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package de.florianreuth.baseproject
+
+import org.gradle.api.Project
+import org.gradle.api.initialization.Settings
+
+/**
+ * Includes `<rootProject.name>-<name>` for every name, located in the `<name>` folder.
+ *
+ * @param names the subproject folder names
+ */
+fun Settings.setupViaSubprojects(vararg names: String) {
+    names.forEach { name ->
+        include("${rootProject.name}-$name")
+        project(":${rootProject.name}-$name").projectDir = settingsDir.resolve(name)
+    }
+}
+
+/**
+ * Version, channel and changelog of a Modrinth / Hangar upload of a ViaVersion project.
+ *
+ * @property isRelease whether the project version has no pre-release suffix
+ * @property isMainBranch whether the current Git branch is the main branch
+ * @property version the project version, suffixed with the GitHub run number for non-releases
+ * @property changelog a link to the GitHub releases for releases, otherwise [commitChangelog]
+ * @property commitChangelog a link to and the message of the latest commit
+ */
+class ViaRelease(
+    val isRelease: Boolean,
+    val isMainBranch: Boolean,
+    val version: String,
+    val changelog: String,
+    val commitChangelog: String
+) {
+    val modrinthVersionType: String
+        get() = if (isRelease) "release" else if (isMainBranch) "beta" else "alpha"
+
+    val hangarChannel: String
+        get() = if (isRelease) "Release" else if (isMainBranch) "Snapshot" else "Alpha"
+}
+
+/**
+ * Collects the release information from the project version and Git; the repository is `ViaVersion/<project_name>`.
+ *
+ * @param mainBranch the name of the branch releases are published from
+ * @return the release information of the current build
+ */
+fun Project.viaRelease(mainBranch: String): ViaRelease {
+    val baseVersion = version.toString()
+    val isRelease = !baseVersion.contains('-')
+    val repository = "https://github.com/ViaVersion/${property("project_name")}"
+    val commitHash = latestCommitHash()
+    val commitChangelog = "[$commitHash]($repository/commit/$commitHash) ${latestCommitMessage()}"
+
+    return ViaRelease(
+        isRelease = isRelease,
+        isMainBranch = branchName() == mainBranch,
+        version = if (isRelease) baseVersion else baseVersion + "+" + System.getenv("GITHUB_RUN_NUMBER"),
+        changelog = if (isRelease) "See [GitHub]($repository) for release notes." else commitChangelog,
+        commitChangelog = commitChangelog
+    )
+}

build-logic/src/main/kotlin/extra.fill_build_constants.gradle.kts

@@ -0,0 +1,20 @@
+import de.florianreuth.baseproject.latestCommitHash
+import net.raphimc.classtokenreplacer.extension.ClassTokenReplacerExtension
+
+plugins {
+    java
+    id("net.raphimc.class-token-replacer")
+}
+
+val implVersion = "git-${property("project_name")}-${project.version}:${latestCommitHash()}"
+sourceSets.configureEach {
+    extensions.getByType<ClassTokenReplacerExtension>().apply {
+        property("\${version}", project.version)
+        property("\${impl_version}", implVersion)
+    }
+}
+
+// With replaceInPlace the plugin only finalizes classes with the replacement, so the jar could pack unreplaced classes
+tasks.jar {
+    dependsOn("replaceTokens")
+}

build-logic/src/main/kotlin/publishing.viaversion.gradle.kts

@@ -0,0 +1,19 @@
+plugins {
+    `maven-publish`
+}
+
+publishing {
+    repositories {
+        maven {
+            name = "Via"
+            url = uri("https://repo.viaversion.com/")
+            credentials {
+                username = findProperty("ViaUsername") as String?
+                password = findProperty("ViaPassword") as String?
+            }
+            authentication {
+                create<BasicAuthentication>("basic")
+            }
+        }
+    }
+}

build-logic/src/main/kotlin/via.addon_subproject.gradle.kts

@@ -0,0 +1,20 @@
+plugins {
+    java
+    id("base.java")
+    id("via.maven_publish")
+}
+
+val libs = project.the<VersionCatalogsExtension>().named("libs")
+
+dependencies {
+    compileOnly(libs.findLibrary("viaversion").get())
+    compileOnly(libs.findLibrary("viabackwards").get())
+}
+
+tasks.processResources {
+    val projectVersion = project.version
+    val projectDescription = project.description
+    filesMatching(listOf("plugin.yml", "fabric.mod.json", "META-INF/sponge_plugins.json")) {
+        expand(mapOf("version" to projectVersion, "description" to projectDescription))
+    }
+}

build-logic/src/main/kotlin/via.maven_publish.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    id("publishing.viaversion")
+}
+
+// base.maven_publish reads these when applied, so it is applied only after they are set
+extra["publish_github_account"] = "ViaVersion"
+extra["publish_license"] = "GPL-3.0"
+apply(plugin = "base.maven_publish")

build-logic/src/main/kotlin/via.run_viaproxy.gradle.kts

@@ -0,0 +1,47 @@
+// Task to quickly test/debug code changes using https://github.com/ViaVersion/ViaProxy
+// For further instructions see the ViaProxy repository README
+plugins {
+    java
+}
+
+val viaProxy = configurations.create("viaProxy")
+
+dependencies {
+    addProvider<MinimalExternalModuleDependency, ExternalModuleDependency>(
+        viaProxy.name,
+        project.the<VersionCatalogsExtension>().named("libs").findLibrary("viaproxy").get()
+    ) {
+        isTransitive = false
+    }
+}
+
+val prepareViaProxyFiles by tasks.registering(Copy::class) {
+    dependsOn(project.tasks.jar)
+
+    from(project.tasks.jar.get().archiveFile.get().asFile)
+    into(layout.projectDirectory.dir("run/jars"))
+
+    val projectName = project.name
+    rename { "${projectName}.jar" }
+}
+
+val cleanupViaProxyFiles by tasks.registering(Delete::class) {
+    delete(
+        layout.projectDirectory.file("run/jars/${project.name}.jar"),
+        layout.projectDirectory.dir("run/logs")
+    )
+}
+
+tasks.register<JavaExec>("runViaProxy") {
+    dependsOn(prepareViaProxyFiles)
+    finalizedBy(cleanupViaProxyFiles)
+
+    mainClass.set("net.raphimc.viaproxy.ViaProxy")
+    classpath = viaProxy
+    workingDir = layout.projectDirectory.dir("run").asFile
+    jvmArgs = listOf("-DskipUpdateCheck")
+
+    if (System.getProperty("viaproxy.gui.autoStart") != null) {
+        jvmArgs("-Dviaproxy.gui.autoStart")
+    }
+}

build.gradle.kts

@@ -1,55 +1,20 @@
-import de.florianmichael.baseproject.*
+import de.florianreuth.baseproject.viaRelease
 
 plugins {
     `java-library`
-    id("io.papermc.hangar-publish-plugin")
-    id("com.modrinth.minotaur")
-    id("de.florianmichael.baseproject.BaseProject")
+    alias(libs.plugins.hangar.publish)
+    alias(libs.plugins.minotaur)
+    id("base.java")
+    id("via.maven_publish")
+    id("configuration.embedded_dependencies")
 }
 
-allprojects {
-
-    setupProject()
-    setupViaPublishing()
-
-    repositories {
-        mavenCentral()
-        maven("https://repo.viaversion.com")
-        maven("https://repo.papermc.io/repository/maven-public")
-        maven("https://maven.fabricmc.net")
-    }
-
-}
-
-subprojects {
-
-    dependencies {
-        compileOnly("com.viaversion:viaversion:5.5.0")
-        compileOnly("com.viaversion:viabackwards:5.5.0")
-    }
-
-    tasks {
-        processResources {
-            val projectVersion = project.version
-            val projectDescription = project.description
-            filesMatching(listOf("plugin.yml", "fabric.mod.json", "META-INF/sponge_plugins.json")) {
-                expand(mapOf("version" to projectVersion, "description" to projectDescription))
-            }
-        }
-    }
-
-}
-
-base {
-    archivesName.set("ViaRewind")
-}
-
-val shade = configureShadedDependencies(false) // Only shade, don't add them as dependency
-
 dependencies {
-    subprojects.forEach {
-        shade(it)
-    }
+    embeddedDependencies(projects.viarewindCommon)
+    embeddedDependencies(projects.viarewindBukkit)
+    embeddedDependencies(projects.viarewindFabric)
+    embeddedDependencies(projects.viarewindSponge)
+    embeddedDependencies(projects.viarewindVelocity)
 }
 
 tasks {
@@ -60,29 +25,18 @@ tasks {
     }
 }
 
-val branch = branchName()
-val baseVersion = version as String
-val isRelease = !baseVersion.contains('-')
-val isMainBranch = branch == "master"
-if (!isRelease || isMainBranch) { // Only publish releases from the main branch
-    val suffixedVersion = if (isRelease) baseVersion else baseVersion + "+" + System.getenv("GITHUB_RUN_NUMBER")
-    val changelogContent = if (isRelease) {
-        "See [GitHub](https://github.com/ViaVersion/ViaRewind) for release notes."
-    } else {
-        val commitHash = latestCommitHash()
-        "[$commitHash](https://github.com/ViaVersion/ViaRewind/commit/$commitHash) ${latestCommitMessage()}"
-    }
-
+val release = viaRelease("master")
+if (!release.isRelease || release.isMainBranch) { // Only publish releases from the main branch
     modrinth {
         val mcVersions: List<String> = (property("minecraft_versions") as String)
             .split(",")
             .map { it.trim() }
         token.set(System.getenv("MODRINTH_TOKEN"))
         projectId.set("viarewind")
-        versionType.set(if (isRelease) "release" else if (isMainBranch) "beta" else "alpha")
-        versionNumber.set(suffixedVersion)
-        versionName.set(suffixedVersion)
-        changelog.set(changelogContent)
+        versionType.set(release.modrinthVersionType)
+        versionNumber.set(release.version)
+        versionName.set(release.version)
+        changelog.set(release.changelog)
         uploadFile.set(tasks.jar.flatMap { it.archiveFile })
         gameVersions.set(mcVersions)
         loaders.add("fabric")
@@ -103,10 +57,10 @@ if (!isRelease || isMainBranch) { // Only publish releases from the main branch
 
     hangarPublish {
         publications.register("plugin") {
-            version.set(suffixedVersion)
+            version.set(release.version)
             id.set("ViaRewind")
-            channel.set(if (isRelease) "Release" else if (isMainBranch) "Snapshot" else "Alpha")
-            changelog.set(changelogContent)
+            channel.set(release.hangarChannel)
+            changelog.set(release.changelog)
             apiKey.set(System.getenv("HANGAR_TOKEN"))
             platforms {
                 paper {

bukkit/build.gradle.kts

@@ -1,4 +1,8 @@
-dependencies {
-    compileOnly(project(":viarewind-common"))
-    compileOnly("org.spigotmc:spigot-api:1.12.2-R0.1-SNAPSHOT")
+plugins {
+    id("via.addon_subproject")
+}
+
+dependencies {
+    compileOnly(projects.viarewindCommon)
+    compileOnly(libs.spigot.api)
 }

bukkit/src/main/java/com/viaversion/viarewind/BukkitPlugin.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -18,8 +18,11 @@
 package com.viaversion.viarewind;
 
 import com.viaversion.viarewind.api.ViaRewindPlatform;
+import com.viaversion.viarewind.protocol.v1_9to1_8.provider.InventoryProvider;
+import com.viaversion.viarewind.provider.BukkitInventoryProvider;
 import com.viaversion.viaversion.api.Via;
 import java.io.File;
+import com.viaversion.viaversion.api.platform.providers.ViaProviders;
 import org.bukkit.plugin.java.JavaPlugin;
 
 public class BukkitPlugin extends JavaPlugin implements ViaRewindPlatform {
@@ -27,4 +30,10 @@ public class BukkitPlugin extends JavaPlugin implements ViaRewindPlatform {
     public BukkitPlugin() {
         Via.getManager().addEnableListener(() -> this.init(new File(getDataFolder(), "config.yml")));
     }
+
+    @Override
+    public void onEnable() {
+        final ViaProviders providers = Via.getManager().getProviders();
+        providers.use(InventoryProvider.class, new BukkitInventoryProvider());
+    }
 }

bukkit/src/main/java/com/viaversion/viarewind/provider/BukkitInventoryProvider.java

@@ -0,0 +1,36 @@
+/*
+ * 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.provider;
+
+import com.viaversion.viarewind.protocol.v1_9to1_8.provider.InventoryProvider;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+
+public final class BukkitInventoryProvider extends InventoryProvider {
+
+    @Override
+    public boolean hasElytra(final UserConnection connection) {
+        final Player player = Bukkit.getPlayer(connection.getProtocolInfo().getUuid());
+        final ItemStack chestplate = player.getInventory().getChestplate();
+        return chestplate != null && chestplate.getType() == Material.ELYTRA;
+    }
+
+}

bukkit/src/main/resources/plugin.yml

@@ -1,6 +1,6 @@
 name: ViaRewind
 main: com.viaversion.viarewind.BukkitPlugin
-authors: [ FlorianMichael/EnZaXD, Gerrygames, creeper123123321 ]
+authors: [ EnZaXD, Gerrygames, creeper123123321 ]
 version: ${version}
 description: ${description}
 website: https://viaversion.com/rewind

common/build.gradle.kts

@@ -1,58 +1,11 @@
-import de.florianmichael.baseproject.latestCommitHash
-
 plugins {
-    id("net.raphimc.class-token-replacer")
+    id("via.addon_subproject")
+    id("extra.fill_build_constants")
+    id("via.run_viaproxy")
 }
 
-val viaProxy: Configuration by configurations.creating
-
 dependencies {
-    compileOnly("io.netty:netty-all:4.0.20.Final")
-    compileOnly("com.google.guava:guava:17.0")
-
-    viaProxy("net.raphimc:ViaProxy:3.4.5-SNAPSHOT") {
-        isTransitive = false
-    }
-}
-
-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) {
-    dependsOn(project.tasks.jar)
-
-    from(project.tasks.jar.get().archiveFile.get().asFile)
-    into(layout.projectDirectory.dir("run/jars"))
-
-    val projectName = project.name
-    rename { "${projectName}.jar" }
-}
-
-val cleanupViaProxyFiles by tasks.registering(Delete::class) {
-    delete(
-        layout.projectDirectory.file("run/jars/${project.name}.jar"),
-        layout.projectDirectory.dir("run/logs")
-    )
-}
-
-tasks.register<JavaExec>("runViaProxy") {
-    dependsOn(prepareViaProxyFiles)
-    finalizedBy(cleanupViaProxyFiles)
-
-    mainClass.set("net.raphimc.viaproxy.ViaProxy")
-    classpath = viaProxy
-    workingDir = layout.projectDirectory.dir("run").asFile
-    jvmArgs = listOf("-DskipUpdateCheck")
-
-    if (System.getProperty("viaproxy.gui.autoStart") != null) {
-        jvmArgs("-Dviaproxy.gui.autoStart")
-    }
+    compileOnly(libs.netty.all)
+    compileOnly(libs.guava)
+    compileOnly(libs.velocity.native)
 }

common/src/main/java/com/viaversion/viarewind/ViaRewind.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/ViaRewindConfig.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/ViaRewindPlatformImpl.java

@@ -0,0 +1,43 @@
+/*
+ * 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;
+
+import com.viaversion.viarewind.api.ViaRewindPlatform;
+import com.viaversion.viaversion.api.Via;
+import java.io.File;
+import java.util.logging.Logger;
+
+public class ViaRewindPlatformImpl implements ViaRewindPlatform {
+
+    private final Logger logger;
+
+    public ViaRewindPlatformImpl() {
+        logger = Via.getPlatform().createLogger("ViaRewind");
+        init(new File(getDataFolder(), "viarewind.yml"));
+    }
+
+    @Override
+    public Logger getLogger() {
+        return logger;
+    }
+
+    @Override
+    public File getDataFolder() {
+        return Via.getPlatform().getDataFolder();
+    }
+}

common/src/main/java/com/viaversion/viarewind/api/ViaRewindConfig.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/ViaRewindPlatform.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -36,11 +36,14 @@ public interface ViaRewindPlatform {
     String VERSION = "${version}";
     String IMPL_VERSION = "${impl_version}";
 
+    default void init(final File configFile) {
+        init(new ViaRewindConfig(configFile, getLogger()));
+    }
+
     /**
      * Initialize ViaRewind
      */
-    default void init(final File configFile) {
-        ViaRewindConfig config = new ViaRewindConfig(configFile, getLogger());
+    default void init(final com.viaversion.viarewind.api.ViaRewindConfig config) {
         config.reload();
         Via.getManager().getConfigurationProvider().register(config);
 
@@ -88,4 +91,13 @@ public interface ViaRewindPlatform {
         return "decompress";
     }
 
+    /**
+     * Returns whether the platform's compression handler also writes the packet length. Only used in the 1.8 -> 1.7 protocol.
+     *
+     * @return true if the compression handler writes the packet length
+     */
+    default boolean compressHandlerWritesLength() {
+        return false;
+    }
+
 }

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/data/RewindMappingDataLoader.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/minecraft/ExtendedBlockStorage.java

@@ -1,77 +0,0 @@
-/*
- * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 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.minecraft;
-
-import com.viaversion.viaversion.api.minecraft.chunks.ChunkSection;
-import com.viaversion.viaversion.api.minecraft.chunks.NibbleArray;
-
-public class ExtendedBlockStorage {
-    private final byte[] blockLSBArray = new byte[ChunkSection.SIZE];
-
-    private final NibbleArray blockMetadataArray = new NibbleArray(this.blockLSBArray.length);
-    private final NibbleArray blockLightArray = new NibbleArray(this.blockLSBArray.length);
-
-    private NibbleArray blockMSBArray;
-    private NibbleArray skyLightArray;
-
-    public ExtendedBlockStorage(final boolean skylight) {
-        if (skylight) {
-            this.skyLightArray = new NibbleArray(this.blockLSBArray.length);
-        }
-    }
-
-    public void setBlockId(final int x, final int y, final int z, final int value) {
-        this.blockLSBArray[ChunkSection.index(x, y, z)] = (byte) (value & 255);
-        if (value > 255) {
-            this.getOrCreateBlockMSBArray().set(x, y, z, (value & 0xF00) >> 8);
-        } else if (this.blockMSBArray != null) {
-            this.blockMSBArray.set(x, y, z, 0);
-        }
-    }
-
-    public void setBlockMetadata(final int x, final int y, final int z, final int value) {
-        this.blockMetadataArray.set(x, y, z, value);
-    }
-
-    public boolean hasBlockMSBArray() {
-        return this.blockMSBArray != null;
-    }
-
-    public byte[] getBlockLSBArray() {
-        return this.blockLSBArray;
-    }
-
-    public NibbleArray getOrCreateBlockMSBArray() {
-        if (this.blockMSBArray == null) {
-            return this.blockMSBArray = new NibbleArray(this.blockLSBArray.length);
-        }
-        return this.blockMSBArray;
-    }
-
-    public NibbleArray getBlockMetadataArray() {
-        return this.blockMetadataArray;
-    }
-
-    public NibbleArray getBlockLightArray() {
-        return this.blockLightArray;
-    }
-
-    public NibbleArray getSkyLightArray() {
-        return this.skyLightArray;
-    }
-}

common/src/main/java/com/viaversion/viarewind/api/minecraft/entitydata/EntityDataTypes1_7_6_10.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/minecraft/math/Ray3d.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/minecraft/math/Vector3d.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/minecraft/netty/EmptyChannelHandler.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/minecraft/netty/ForwardMessageToByteEncoder.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -17,14 +17,24 @@
  */
 package com.viaversion.viarewind.api.minecraft.netty;
 
+import com.viaversion.viaversion.api.type.Types;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToByteEncoder;
 
 public class ForwardMessageToByteEncoder extends MessageToByteEncoder<ByteBuf> {
 
+    private final boolean writeLength;
+
+    public ForwardMessageToByteEncoder(final boolean writeLength) {
+        this.writeLength = writeLength;
+    }
+
     @Override
     protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) {
+        if (writeLength) {
+            Types.VAR_INT.writePrimitive(out, msg.readableBytes());
+        }
         out.writeBytes(msg);
     }
 }

common/src/main/java/com/viaversion/viarewind/api/rewriter/VRBlockItemRewriter.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/rewriter/VREntityRewriter.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/IntArrayType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/PositionVarYType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/RewindTypes.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -28,7 +28,6 @@ import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.Types;
-import com.viaversion.viaversion.libs.gson.JsonElement;
 import java.util.List;
 
 /**
@@ -36,7 +35,6 @@ import java.util.List;
  */
 public class RewindTypes {
 
-    public static final Type<JsonElement> SIGN_COMPONENT = new SignComponentType();
     public static final Type<int[]> INT_ARRAY = new IntArrayType(); // Integer array with byte as length indicator
 
     public static final Type<BlockPosition> SHORT_POSITION = new PositionVarYType<>(Types.SHORT, value -> (short) value);

common/src/main/java/com/viaversion/viarewind/api/type/SignComponentType.java

@@ -1,51 +0,0 @@
-/*
- * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 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.type;
-
-import com.viaversion.viaversion.api.Via;
-import com.viaversion.viaversion.api.type.Type;
-import com.viaversion.viaversion.api.type.types.ComponentType;
-import com.viaversion.viaversion.api.type.types.StringType;
-import com.viaversion.viaversion.libs.gson.JsonElement;
-import com.viaversion.viaversion.libs.gson.JsonParser;
-import com.viaversion.viaversion.libs.gson.JsonSyntaxException;
-import io.netty.buffer.ByteBuf;
-
-public class SignComponentType extends ComponentType {
-
-    public static final Type<String> STRING = new StringType(384);
-
-    @Override
-    public JsonElement read(final ByteBuf buffer) {
-        final String string = STRING.read(buffer);
-        try {
-            return JsonParser.parseString(string);
-        } catch (final JsonSyntaxException e) {
-            if (Via.getManager().isDebug()) {
-                Via.getPlatform().getLogger().severe("Error when trying to parse json: " + string);
-            }
-            throw e;
-        }
-    }
-
-    @Override
-    public void write(final ByteBuf buffer, final JsonElement value) {
-        STRING.write(buffer, value.toString());
-    }
-
-}

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -17,12 +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.minecraft.chunks.ChunkSection;
 import com.viaversion.viaversion.api.type.Type;
-import com.viaversion.viaversion.util.Pair;
 import io.netty.buffer.ByteBuf;
-import java.util.zip.Deflater;
+
+import java.util.zip.DataFormatException;
+
 
 public class BulkChunkType1_7_6 extends Type<Chunk[]> {
 
@@ -38,73 +39,80 @@ public class BulkChunkType1_7_6 extends Type<Chunk[]> {
     }
 
     @Override
-    public void write(ByteBuf byteBuf, Chunk[] chunks) {
+    public void write(ByteBuf buffer, Chunk[] chunks) {
         final int chunkCount = chunks.length;
-        final int[] chunkX = new int[chunkCount];
-        final int[] chunkZ = new int[chunkCount];
-        final short[] primaryBitMask = new short[chunkCount];
-        final short[] additionalBitMask = new short[chunkCount];
+        final int[] addBitMasks = new int[chunkCount];
+        int totalSize = 0;
+        boolean anySkyLight = false;
 
-        final byte[][] dataArrays = new byte[chunkCount][];
-        int dataSize = 0;
-
-        for (int i = 0; i < chunkCount; i++) {
-            final Chunk chunk = chunks[i];
-            Pair<byte[], Short> chunkData;
-            try {
-                chunkData = ChunkType1_7_6.serialize(chunk);
-                final byte[] data = chunkData.key();
-                dataArrays[i] = data;
-                dataSize += data.length;
-            } catch (Exception e) {
-                throw new RuntimeException("Unable to serialize chunk", e);
-            }
-            chunkX[i] = chunk.getX();
-            chunkZ[i] = chunk.getZ();
-            primaryBitMask[i] = (short) chunk.getBitmask();
-            additionalBitMask[i] = chunkData.value();
-        }
-
-        final byte[] data = new byte[dataSize];
-        int destPos = 0;
-        for (final byte[] array : dataArrays) {
-            System.arraycopy(array, 0, data, destPos, array.length);
-            destPos += array.length;
-        }
-
-        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();
-        }
-
-        byteBuf.writeShort(chunkCount);
-        byteBuf.writeInt(compressedSize);
-
-        boolean skyLight = false;
         for (Chunk chunk : chunks) {
-            for (ChunkSection section : chunk.getSections()) {
-                if (section != null && section.getLight().hasSkyLight()) {
-                    skyLight = true;
-                    break;
-                }
+            if (ChunkType1_7_6.hasSkyLight(chunk)) {
+                anySkyLight = true;
+                break;
             }
         }
 
-        byteBuf.writeBoolean(skyLight); // hasSkyLight
-        byteBuf.writeBytes(compressedData, 0, compressedSize);
+        for (int i = 0; i < chunkCount; i++) {
+            Chunk chunk = chunks[i];
+            addBitMasks[i] = ChunkType1_7_6.getAddBitMask(chunk);
+            boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
+
+            totalSize += ChunkType1_7_6.calcSize(
+                chunk.getBitmask(),
+                addBitMasks[i],
+                anySkyLight,
+                biomes
+            );
+        }
+
+        final ByteBuf uncompressed = buffer.alloc().buffer(totalSize);
+
+        try {
+            for (int i = 0; i < chunkCount; i++) {
+                Chunk chunk = chunks[i];
+                boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
+
+                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++) {
-            byteBuf.writeInt(chunkX[i]);
-            byteBuf.writeInt(chunkZ[i]);
-            byteBuf.writeShort(primaryBitMask[i]);
-            byteBuf.writeShort(additionalBitMask[i]);
+            Chunk chunk = chunks[i];
+            buffer.writeInt(chunk.getX());
+            buffer.writeInt(chunk.getZ());
+            buffer.writeShort(chunk.getBitmask());
+            buffer.writeShort(addBitMasks[i]);
         }
     }
 }

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -17,15 +17,15 @@
  */
 package com.viaversion.viarewind.api.type.chunk;
 
-import com.viaversion.viarewind.api.minecraft.ExtendedBlockStorage;
+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 com.viaversion.viaversion.util.Pair;
 import io.netty.buffer.ByteBuf;
-import java.io.IOException;
-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;
@@ -38,143 +38,170 @@ public class ChunkType1_7_6 extends Type<Chunk> {
         super(Chunk.class);
     }
 
-    public static Pair<byte[], Short> serialize(final Chunk chunk) throws IOException {
-        final ExtendedBlockStorage[] storageArrays = new ExtendedBlockStorage[16];
-        for (int i = 0; i < storageArrays.length; i++) {
-            final ChunkSection section = chunk.getSections()[i];
-            if (section != null) {
-                final ExtendedBlockStorage storage = storageArrays[i] = new ExtendedBlockStorage(section.getLight().hasSkyLight());
-                for (int x = 0; x < 16; x++) {
-                    for (int z = 0; z < 16; z++) {
-                        for (int y = 0; y < 16; y++) {
-                            final int flatBlock = section.palette(PaletteType.BLOCKS).idAt(x, y, z);
-                            storage.setBlockId(x, y, z, flatBlock >> 4);
-                            storage.setBlockMetadata(x, y, z, flatBlock & 15);
-                        }
-                    }
-                }
-                storage.getBlockLightArray().setHandle(section.getLight().getBlockLight());
-                if (section.getLight().hasSkyLight()) {
-                    storage.getSkyLightArray().setHandle(section.getLight().getSkyLight());
-                }
-            }
-        }
-
-        final boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
-        final int totalSize = calculateSize(storageArrays, chunk.getBitmask(), biomes);
-
-        final byte[] output = new byte[totalSize];
-        int index = 0;
-
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((chunk.getBitmask() & 1 << i) != 0) {
-                final byte[] blockLSBArray = storageArrays[i].getBlockLSBArray();
-                System.arraycopy(blockLSBArray, 0, output, index, blockLSBArray.length);
-                index += blockLSBArray.length;
-            }
-        }
-
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((chunk.getBitmask() & 1 << i) != 0) {
-                final byte[] blockMetadataArray = storageArrays[i].getBlockMetadataArray().getHandle();
-                System.arraycopy(blockMetadataArray, 0, output, index, blockMetadataArray.length);
-                index += blockMetadataArray.length;
-            }
-        }
-
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((chunk.getBitmask() & 1 << i) != 0) {
-                final byte[] blockLightArray = storageArrays[i].getBlockLightArray().getHandle();
-                System.arraycopy(blockLightArray, 0, output, index, blockLightArray.length);
-                index += blockLightArray.length;
-            }
-        }
-
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((chunk.getBitmask() & 1 << i) != 0 && storageArrays[i].getSkyLightArray() != null) {
-                final byte[] skyLightArray = storageArrays[i].getSkyLightArray().getHandle();
-                System.arraycopy(skyLightArray, 0, output, index, skyLightArray.length);
-                index += skyLightArray.length;
-            }
-        }
-
-        short additionalBitMask = 0;
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((chunk.getBitmask() & 1 << i) != 0 && storageArrays[i].hasBlockMSBArray()) {
-                additionalBitMask |= (short) (1 << i);
-                final byte[] blockMSBArray = storageArrays[i].getOrCreateBlockMSBArray().getHandle();
-                System.arraycopy(blockMSBArray, 0, output, index, blockMSBArray.length);
-                index += blockMSBArray.length;
-            }
-        }
-
-        if (biomes) {
-            for (int biome : chunk.getBiomeData()) {
-                output[index++] = (byte) biome;
-            }
-        }
-
-        return new Pair<>(output, additionalBitMask);
-    }
-
-    private static int calculateSize(final ExtendedBlockStorage[] storageArrays, final int bitmask, final boolean biomes) {
-        int totalSize = 0;
-        for (int i = 0; i < storageArrays.length; i++) {
-            if ((bitmask & 1 << i) != 0) {
-                totalSize += SIZE; // Block lsb array
-                totalSize += SIZE / 2; // Block metadata array
-                totalSize += LIGHT_LENGTH; // Block light array
-
-                if (storageArrays[i].getSkyLightArray() != null) {
-                    totalSize += LIGHT_LENGTH;
-                }
-
-                if (storageArrays[i].hasBlockMSBArray()) {
-                    totalSize += SIZE / 2; // Block msb array
-                }
-            }
-        }
-        if (biomes) {
-            totalSize += 256;
-        }
-        return totalSize;
-    }
-
     @Override
     public Chunk read(ByteBuf byteBuf) {
         throw new UnsupportedOperationException(); // Not needed, see https://github.com/ViaVersion/ViaLegacy/blob/main/src/main/java/net/raphimc/vialegacy/protocols/release/protocol1_8to1_7_6_10/types/Chunk1_7_6Type.java
     }
 
     @Override
-    public void write(ByteBuf output, Chunk chunk) {
-        Pair<byte[], Short> chunkData;
-        try {
-            chunkData = serialize(chunk);
-        } catch (IOException e) {
-            throw new RuntimeException("Unable to serialize chunk", e);
-        }
-        final byte[] data = chunkData.key();
-        final short additionalBitMask = chunkData.value();
+    public void write(ByteBuf buffer, Chunk chunk) {
+        final int bitmask = chunk.getBitmask();
+        final int addBitmask = getAddBitMask(chunk);
+        final boolean hasSkyLight = hasSkyLight(chunk);
+        final boolean biomes = chunk.isFullChunk() && chunk.getBiomeData() != null;
+
+        final int size = calcSize(bitmask, addBitmask, hasSkyLight, biomes);
+        final ByteBuf uncompressed = buffer.alloc().buffer(size);
 
-        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);
+            serialize(chunk, uncompressed, addBitmask, hasSkyLight, biomes);
+
+            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 {
-            deflater.end();
+            uncompressed.release();
         }
-
-        output.writeInt(chunk.getX());
-        output.writeInt(chunk.getZ());
-        output.writeBoolean(chunk.isFullChunk());
-        output.writeShort(chunk.getBitmask());
-        output.writeShort(additionalBitMask);
-        output.writeInt(compressedSize);
-        output.writeBytes(compressedData, 0, compressedSize);
     }
 
+    public static void serialize(Chunk chunk, ByteBuf output, int addBitmask, boolean writeSkyLight, boolean biomes) {
+        final ChunkSection[] sections = chunk.getSections();
+        final int bitmask = chunk.getBitmask();
+
+        for (int i = 0; i < 16; i++) {
+            if ((bitmask & (1 << i)) != 0) {
+                final ChunkSection section = sections[i];
+                final DataPalette palette = section.palette(PaletteType.BLOCKS);
+                for (int j = 0; j < SIZE; j++) {
+                    final int block = palette.idAt(j);
+                    output.writeByte((block >> 4) & 0xFF);
+                }
+            }
+        }
+
+        for (int i = 0; i < 16; i++) {
+            if ((bitmask & (1 << i)) != 0) {
+                final ChunkSection section = sections[i];
+                final DataPalette palette = section.palette(PaletteType.BLOCKS);
+                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.writeByte(meta1 | (meta2 << 4));
+                }
+            }
+        }
+
+        for (int i = 0; i < 16; i++) {
+            if ((bitmask & (1 << i)) != 0) {
+                final byte[] blockLight = sections[i].getLight().getBlockLight();
+                output.writeBytes(blockLight);
+            }
+        }
+
+        if (writeSkyLight) {
+            for (int i = 0; i < 16; i++) {
+                if ((bitmask & (1 << i)) != 0) {
+                    if (sections[i].getLight().hasSkyLight()) {
+                        final byte[] skyLight = sections[i].getLight().getSkyLight();
+                        output.writeBytes(skyLight);
+                    } else {
+                        // Write empty skylight data
+                        output.writeZero(LIGHT_LENGTH);
+                    }
+                }
+            }
+        }
+
+        if (addBitmask != 0) {
+            for (int i = 0; i < 16; i++) {
+                if ((bitmask & (1 << i)) != 0 && (addBitmask & (1 << i)) != 0) {
+                    final ChunkSection section = sections[i];
+                    final DataPalette palette = section.palette(PaletteType.BLOCKS);
+                    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.writeByte(add1 | (add2 << 4));
+                    }
+                }
+            }
+        }
+
+        if (biomes && chunk.getBiomeData() != null) {
+            final int[] biomeData = chunk.getBiomeData();
+            for (int biome : biomeData) {
+                output.writeByte(biome);
+            }
+        }
+    }
+
+    public static int calcSize(int bitmask, int addBitmask, boolean hasSkyLight, boolean biomes) {
+        int size = 0;
+        int sections = Integer.bitCount(bitmask);
+
+        size += sections * SIZE;
+        size += sections * (SIZE / 2);
+        size += sections * LIGHT_LENGTH;
+
+        if (hasSkyLight) {
+            size += sections * LIGHT_LENGTH;
+        }
+
+        if (addBitmask != 0) {
+            size += Integer.bitCount(addBitmask) * (SIZE / 2);
+        }
+
+        if (biomes) {
+            size += 256;
+        }
+
+        return size;
+    }
+
+    public static int getAddBitMask(Chunk chunk) {
+        int addBitMask = 0;
+        for (int i = 0; i < 16; i++) {
+            if ((chunk.getBitmask() & (1 << i)) != 0) {
+                final ChunkSection section = chunk.getSections()[i];
+                final DataPalette palette = section.palette(PaletteType.BLOCKS);
+                for (int j = 0; j < SIZE; j++) {
+                    final int id = palette.idAt(j);
+                    if ((id >> 12) != 0) {
+                        addBitMask |= (1 << i);
+                        break;
+                    }
+                }
+            }
+        }
+        return addBitMask;
+    }
+
+    public static boolean hasSkyLight(Chunk chunk) {
+        for (ChunkSection section : chunk.getSections()) {
+            if (section != null && section.getLight().hasSkyLight()) {
+                return true;
+            }
+        }
+        return false;
+    }
 }

common/src/main/java/com/viaversion/viarewind/api/type/entitydata/EntityDataListType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/entitydata/EntityDataType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/item/ItemArrayType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/item/ItemType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/api/type/item/NBTType.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_7_6_10to1_7_2_5/Protocol1_7_6_10To1_7_2_5.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_7_6_10to1_7_2_5/packet/ClientboundPackets1_7_2_5.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_7_6_10to1_7_2_5/packet/ServerboundPackets1_7_2_5.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/ChatItemRewriter.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -0,0 +1,234 @@
+/*
+ * 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.data;
+
+import com.viaversion.viaversion.libs.gson.JsonArray;
+import com.viaversion.viaversion.libs.gson.JsonElement;
+import com.viaversion.viaversion.libs.gson.JsonObject;
+
+import java.util.ArrayList;
+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());
+    }
+
+    private static List<JsonObject> splitChatComponentByNewline(JsonElement element, JsonObject inheritedStyle) {
+        List<JsonObject> results = new ArrayList<>();
+        if (element == null || element.isJsonNull()) {
+            return results;
+        }
+
+        if (element.isJsonPrimitive()) {
+            String text = element.getAsString();
+            for (String part : text.split("\n", -1)) {
+                JsonObject obj = inheritedStyle.deepCopy();
+                obj.addProperty("text", part);
+                results.add(obj);
+            }
+            return results;
+        }
+
+        if (element.isJsonArray()) {
+            List<JsonObject> currentLine = new ArrayList<>();
+            JsonObject siblingStyle = inheritedStyle;
+            boolean foundRoot = false;
+
+            for (JsonElement child : element.getAsJsonArray()) {
+                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;
+        }
+
+        if (!element.isJsonObject()) {
+            return results;
+        }
+
+        JsonObject obj = element.getAsJsonObject();
+
+        // Build the style for this node: inherit first, then override with this object's style
+        JsonObject currentStyle = mergeStyle(inheritedStyle, obj);
+
+        // Gather components in order: base text then extra array
+        List<JsonElement> ordered = new ArrayList<>();
+        if (obj.has("text")) {
+            ordered.add(obj.get("text"));
+        }
+        if (obj.has("extra") && obj.get("extra").isJsonArray()) {
+            for (JsonElement extra : obj.getAsJsonArray("extra")) {
+                ordered.add(extra);
+            }
+        }
+
+        // If there is no text/extra, return a single object with the style
+        if (ordered.isEmpty()) {
+            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;
+            }
+
+            if (part.isJsonPrimitive()) {
+                String text = part.getAsString();
+                String[] split = text.split("\n", -1);
+                for (int i = 0; i < split.length; i++) {
+                    JsonObject piece = currentStyle.deepCopy();
+                    piece.addProperty("text", split[i]);
+                    currentLine.add(piece);
+
+                    if (i < split.length - 1) {
+                        results.add(mergeLine(currentLine));
+                        currentLine.clear();
+                    }
+                }
+                continue;
+            }
+
+            if (part.isJsonObject() || part.isJsonArray()) {
+                List<JsonObject> splitParts = splitChatComponentByNewline(part, currentStyle);
+                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 (!currentLine.isEmpty()) {
+            results.add(mergeLine(currentLine));
+        }
+
+        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();
+            empty.addProperty("text", "");
+            return empty;
+        }
+
+        JsonObject first = lineParts.get(0);
+        if (lineParts.size() == 1) {
+            return first;
+        }
+
+        JsonObject merged = new JsonObject();
+        merged.addProperty("text", "");
+
+        JsonArray extra = new JsonArray();
+        for (JsonObject linePart : lineParts) {
+            extra.add(linePart);
+        }
+        merged.add("extra", extra);
+        return merged;
+    }
+}

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/data/EntityDataIndex1_7_6_10.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/data/Particles1_8.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -24,6 +24,7 @@ import com.viaversion.viarewind.api.type.RewindTypes;
 import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ClientboundPackets1_7_2_5;
 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.rewriter.EntityPacketRewriter1_8;
+import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.EntityTracker1_8;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_8;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
@@ -46,6 +47,8 @@ public class VirtualHologramEntity {
     private String name = null;
     private float yaw, pitch;
     private float headYaw;
+    private byte flags = 0;
+    private byte armorStandFlags = 0;
     private boolean small = false;
     private boolean marker = false;
     private boolean sneaking = false;
@@ -99,8 +102,6 @@ public class VirtualHologramEntity {
         }
 
         // Filter armor stand data to calculate emulation
-        byte flags = 0;
-        byte armorStandFlags = 0;
         for (EntityData entityData : entityDataTracker) {
             if (entityData.id() == 0 && entityData.dataType() == EntityDataTypes1_8.BYTE) {
                 flags = ((Number) entityData.getValue()).byteValue();
@@ -120,7 +121,7 @@ public class VirtualHologramEntity {
         gravity = (armorStandFlags & 0x02) == 0;
 
         State prevState = currentState;
-        if (invisible && name != null) {
+        if (invisible && name != null && alwaysShowNametag == 1) {
             currentState = State.HOLOGRAM;
         } else if (gravity) {
             currentState = State.ZOMBIE;
@@ -167,6 +168,18 @@ public class VirtualHologramEntity {
             } else {
                 return baseOffset + (0.9875 * 2);
             }
+        } else if (currentState == State.ZOMBIE_NO_GRAVITY) {
+            // 1.7 ride stack offset sum: Squid (0.95 * 0.75) + Zombie (1.8 * 0.75) = 2.0625
+            // By starting at -2.0625, we zero out the 1.7 passenger height so we can apply 1.8's offsets.
+            double baseOffset = -2.0625;
+
+            if (marker) {
+                // 1.8 Marker ArmorStand height is 0.0 -> mounted offset 0.0
+                return baseOffset;
+            } else {
+                // 1.8 Normal ArmorStand height is 1.975 -> mounted offset 1.975 * 0.75 = 1.48125
+                return baseOffset + 1.48125;
+            }
         } else {
             return -0.4;
         }
@@ -291,6 +304,13 @@ public class VirtualHologramEntity {
             this.entityIds = entityIds;
         }
 
+        for (int extraId : entityIds) {
+            if (extraId != entityId) {
+                ((EntityTracker1_8) user.getEntityTracker(Protocol1_8To1_7_6_10.class)).setExtraHologramId(entityId, extraId);
+            }
+        }
+
+
         sendEntityDataUpdate(entityRewriter);
         if (entityIds == null) {
             return;
@@ -326,6 +346,13 @@ public class VirtualHologramEntity {
         if (entityIds == null) {
             return;
         }
+
+        for (int extraId : entityIds) {
+            if (extraId != entityId) {
+                ((EntityTracker1_8) user.getEntityTracker(Protocol1_8To1_7_6_10.class)).removeExtraHologramId(extraId);
+            }
+        }
+
         final PacketWrapper despawn = PacketWrapper.create(ClientboundPackets1_7_2_5.REMOVE_ENTITIES, user);
         despawn.write(Types.BYTE, (byte) entityIds.length);
         for (int id : entityIds) {

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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 {
 
@@ -28,9 +27,6 @@ public abstract class CompressionHandlerProvider implements Provider {
 
     public abstract void onTransformPacket(UserConnection user);
 
-    public abstract ChannelHandler getEncoder(int threshold);
-
-    public abstract ChannelHandler getDecoder(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/TitleRenderProvider.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -17,17 +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.Inflater;
 
 public class CompressionDecoder extends MessageToMessageDecoder<ByteBuf> {
-    private final Inflater inflater = new Inflater();
 
     private int threshold;
 
@@ -41,7 +39,9 @@ public class CompressionDecoder extends MessageToMessageDecoder<ByteBuf> {
 
     @Override
     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
-        if (!in.isReadable()) return;
+        if (!in.isReadable()) {
+            return;
+        }
 
         int outLength = Types.VAR_INT.readPrimitive(in);
         if (outLength == 0) {
@@ -55,21 +55,13 @@ public class CompressionDecoder extends MessageToMessageDecoder<ByteBuf> {
             throw new DecoderException("Badly compressed packet - size of " + outLength + " is larger than protocol maximum of " + 2097152);
         }
 
-        ByteBuf temp = in;
-        if (!in.hasArray()) {
-            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(in);
-        } else {
-            in.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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -17,15 +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.Deflater;
 
 public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
-    private final Deflater deflater = new Deflater();
 
     private int threshold;
 
@@ -47,27 +45,7 @@ public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
         }
 
         Types.VAR_INT.writePrimitive(out, frameLength);
-
-        ByteBuf temp = in;
-        if (!in.hasArray()) {
-            temp = ByteBufAllocator.DEFAULT.heapBuffer().writeBytes(in);
-        } else {
-            in.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()));
-            }
-            out.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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -23,7 +23,6 @@ import com.viaversion.viarewind.api.minecraft.netty.ForwardMessageToByteEncoder;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.CompressionHandlerProvider;
 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 {
@@ -41,7 +40,7 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
         if (encoder != null) {
             encoder.setThreshold(threshold);
         } else {
-            pipeline.addBefore(Via.getManager().getInjector().getEncoderName(), compressHandlerName, getEncoder(threshold));
+            pipeline.addBefore(Via.getManager().getInjector().getEncoderName(), compressHandlerName, new CompressionEncoder(threshold));
         }
 
         final String decompressHandlerName = ViaRewind.getPlatform().decompressHandlerName();
@@ -49,7 +48,7 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
         if (decoder != null) {
             decoder.setThreshold(threshold);
         } else {
-            pipeline.addBefore(Via.getManager().getInjector().getDecoderName(), decompressHandlerName, getDecoder(threshold));
+            pipeline.addBefore(Via.getManager().getInjector().getDecoderName(), decompressHandlerName, new CompressionDecoder(threshold));
         }
     }
 
@@ -67,7 +66,7 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
 
             if (compressor != null) { // We can neutralize the effect of compressor to the client
                 pipeline.replace(decompressor, decompressor, new EmptyChannelHandler());
-                pipeline.replace(compressor, compressor, new ForwardMessageToByteEncoder());
+                pipeline.replace(compressor, compressor, new ForwardMessageToByteEncoder(ViaRewind.getPlatform().compressHandlerWritesLength()));
             } else {
                 throw new IllegalStateException("Couldn't remove compression for 1.7!");
             }
@@ -76,13 +75,5 @@ public class TrackingCompressionHandlerProvider extends CompressionHandlerProvid
         }
     }
 
-    @Override
-    public ChannelHandler getEncoder(int threshold) {
-        return new CompressionEncoder(threshold);
-    }
 
-    @Override
-    public ChannelHandler getDecoder(int threshold) {
-        return new CompressionDecoder(threshold);
-    }
 }

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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());
@@ -337,6 +337,11 @@ public class EntityPacketRewriter1_8 extends VREntityRewriter<ClientboundPackets
                 map(Types.ENTITY_DATA_LIST1_8, RewindTypes.ENTITY_DATA_LIST1_7); // Entity data
 
                 handler(getTrackerAndDataHandler(RewindTypes.ENTITY_DATA_LIST1_7, EntityTypes1_8.EntityType.PLAYER));
+                handler(wrapper -> {
+                    final int entityId = wrapper.get(Types.VAR_INT, 0);
+                    final EntityTracker1_8 tracker = tracker(wrapper.user());
+                    tracker.checkNametagVisibility(entityId);
+                });
             }
         });
         protocol.registerClientbound(ClientboundPackets1_8.SET_EQUIPPED_ITEM, new PacketHandlers() {
@@ -349,7 +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;
@@ -359,7 +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) {
@@ -391,7 +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)));
             }
         });
 
@@ -419,7 +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) {
@@ -443,7 +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) {
@@ -469,7 +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) {
@@ -501,7 +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;
@@ -532,7 +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) {
@@ -554,7 +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);
@@ -589,7 +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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -30,6 +30,7 @@ import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ClientboundPa
 import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ServerboundPackets1_7_2_5;
 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.ChatItemRewriter;
+import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.data.ChatNewlineRewriter;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.TitleRenderProvider;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.EntityTracker1_8;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.GameProfileStorage;
@@ -37,6 +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;
@@ -46,6 +48,8 @@ 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.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;
@@ -70,13 +74,27 @@ public class PlayerPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6_10>
             @Override
             public void register() {
                 map(Types.COMPONENT); // Chat message
+
                 handler(wrapper -> {
                     final JsonElement json = wrapper.get(Types.COMPONENT, 0);
-                    ChatItemRewriter.toClient(protocol, wrapper.user(), json);
-
                     final int position = wrapper.read(Types.BYTE);
+
                     if (position == 2) { // Above hotbar
                         wrapper.cancel();
+                        return;
+                    }
+
+                    ChatItemRewriter.toClient(protocol, wrapper.user(), json);
+                    List<JsonObject> splitComponents = ChatNewlineRewriter.splitChatComponentByNewline(json);
+
+                    if (splitComponents.size() > 1) {
+                        wrapper.cancel();
+
+                        for (JsonObject split : splitComponents) {
+                            PacketWrapper newWrapper = wrapper.create(ClientboundPackets1_7_2_5.CHAT);
+                            newWrapper.write(Types.COMPONENT, split);
+                            newWrapper.send(Protocol1_8To1_7_6_10.class);
+                        }
                     }
                 });
             }
@@ -111,13 +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());
@@ -178,7 +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();
                     }
@@ -204,7 +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];
@@ -276,7 +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) {
@@ -429,7 +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);
             }
@@ -490,12 +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();
 
@@ -513,16 +537,20 @@ 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);
+                    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);
+
+                    if (entityId == -1) {
+                        return;
+                    }
+
+                    wrapper.set(Types.VAR_INT, 0, entityId);
+
                     if (mode != 0) {
                         return;
                     }
-                    final int entityId = wrapper.get(Types.VAR_INT, 0);
-                    final EntityTracker1_8 tracker = wrapper.user().getEntityTracker(Protocol1_8To1_7_6_10.class);
-                    final PlayerSessionStorage position = wrapper.user().get(PlayerSessionStorage.class);
 
-                    if (!tracker.getHolograms().containsKey(entityId)) {
-                        return;
-                    }
                     final AABB boundingBox = tracker.getHolograms().get(entityId).getBoundingBox();
 
                     Vector3d pos = new Vector3d(position.getPosX(), position.getPosY() + 1.8, position.getPosZ());
@@ -590,6 +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);
+                });
             }
         });
 
@@ -600,6 +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)));
             }
         });
@@ -672,7 +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());
@@ -752,6 +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() {
@@ -762,7 +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": {
@@ -779,17 +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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -19,6 +19,7 @@ package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.rewriter;
 
 import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ClientboundPackets1_7_2_5;
 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.storage.EntityTracker1_8;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.ScoreboardTracker;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
@@ -173,6 +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(protocol);
 
             final byte mode = wrapper.passthrough(Types.BYTE);
             if (mode != 0 && !scoreboard.teamExists(team)) {
@@ -190,6 +192,10 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
             if (mode == 0) {
                 scoreboard.addTeam(team);
             } else if (mode == 1) {
+                // Team removed, nametag visibility might have changed
+                for (final String member : scoreboard.getTeamMembers(team)) {
+                    tracker.checkNametagVisbility(member);
+                }
                 scoreboard.removeTeam(team);
             }
 
@@ -198,7 +204,9 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
                 wrapper.passthrough(Types.STRING); // Prefix
                 wrapper.passthrough(Types.STRING); // Suffix
                 wrapper.passthrough(Types.BYTE); // Friendly fire
-                wrapper.read(Types.STRING); // Name tag visibility
+                final String nameTagVisibility = wrapper.read(Types.STRING);
+                final String previousVisibility = scoreboard.getTeamNameTagVisibility(team);
+                scoreboard.setTeamNameTagVisibility(team, nameTagVisibility);
                 byte color = wrapper.read(Types.BYTE);
                 if (mode == 2 && scoreboard.getTeamColor(team).get() != color) {
                     final String sidebar = scoreboard.getColorDependentSidebar().get(color);
@@ -209,6 +217,13 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
                     sidebarPacket.scheduleSend(Protocol1_8To1_7_6_10.class);
                 }
                 scoreboard.setTeamColor(team, color);
+
+                // Re-evaluate nametag visibility for all team members when visibility changes
+                if (mode == 2 && !nameTagVisibility.equals(previousVisibility)) {
+                    for (final String member : scoreboard.getTeamMembers(team)) {
+                        tracker.checkNametagVisbility(member);
+                    }
+                }
             }
             if (mode == 0 || mode == 3 || mode == 4) {
                 byte color = scoreboard.getTeamColor(team).get();
@@ -223,6 +238,8 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
                             continue;
                         }
                         scoreboard.removePlayerFromTeam(entry, team);
+                        // Player left team, nametag visibility may change
+                        tracker.checkNametagVisbility(entry);
                         if (entry.equals(username)) {
                             final PacketWrapper sidebarPacket = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_DISPLAY_OBJECTIVE, wrapper.user());
                             sidebarPacket.write(Types.BYTE, (byte) 1);
@@ -231,6 +248,8 @@ public class ScoreboardPacketRewriter1_8 extends RewriterBase<Protocol1_8To1_7_6
                         }
                     } else {
                         scoreboard.addPlayerToTeam(entry, team);
+                        // Player joined team, nametag visibility may change
+                        tracker.checkNametagVisbility(entry);
                         if (entry.equals(username) && scoreboard.getColorDependentSidebar().containsKey(color)) {
                             final PacketWrapper displayObjective = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_DISPLAY_OBJECTIVE, wrapper.user());
                             displayObjective.write(Types.BYTE, (byte) 1);

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/CompressionStatusTracker.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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;
@@ -37,18 +38,26 @@ import com.viaversion.viaversion.libs.fastutil.objects.Object2IntMap;
 import com.viaversion.viaversion.libs.fastutil.objects.Object2IntOpenHashMap;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_8;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 import java.util.UUID;
 import java.util.logging.Level;
 
+import com.viaversion.viarewind.api.minecraft.entitydata.EntityDataTypes1_7_6_10;
+import com.viaversion.viarewind.api.type.RewindTypes;
+import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ClientboundPackets1_7_2_5;
+
 public class EntityTracker1_8 extends EntityTrackerBase {
 
     private final Int2ObjectMap<VirtualHologramEntity> holograms = new Int2ObjectArrayMap<>();
+    private final Int2IntMap extraHologramIds = new Int2IntArrayMap();
     private final Int2IntMap vehicles = new Int2IntArrayMap();
     private final Int2ObjectMap<UUID> entityIdToUUID = new Int2ObjectArrayMap<>();
     private final Object2IntMap<UUID> entityUUIDToId = new Object2IntOpenHashMap<>();
+    private final Int2IntMap playerNametagHiderEntities = new Int2IntArrayMap();
 
     private final List<EntityData> entityData = new ArrayList<>();
 
@@ -60,35 +69,41 @@ 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();
             holograms.remove(entityId);
         }
 
+        if (playerNametagHiderEntities.containsKey(entityId)) {
+            despawnNametagHiderEntity(entityId);
+        }
+
         if (entityIdToUUID.containsKey(entityId)) {
             final UUID playerId = entityIdToUUID.remove(entityId);
 
             entityUUIDToId.removeInt(playerId);
             user().get(PlayerSessionStorage.class).getPlayerEquipment().remove(playerId);
         }
+        return super.removeEntity(entityId);
     }
 
     @Override
     public void clearEntities() {
         super.clearEntities();
+        holograms.clear();
+        extraHologramIds.clear();
         vehicles.clear();
+        playerNametagHiderEntities.clear();
     }
 
     @Override
@@ -155,6 +170,11 @@ public class EntityTracker1_8 extends EntityTrackerBase {
         } else {
             vehicles.put(vehicleId, passengerId);
         }
+
+        // Re-evaluate nametag visibility when a player entity's passenger changes
+        if (vehicleId != -1 && entityIdToUUID.containsKey(vehicleId)) {
+            checkNametagVisibility(vehicleId);
+        }
     }
 
     protected void attachEntity(final int target) {
@@ -185,10 +205,111 @@ public class EntityTracker1_8 extends EntityTrackerBase {
         }
     }
 
+    public void checkNametagVisibility(final int entityId) {
+        if (!entityIdToUUID.containsKey(entityId)) {
+            return;
+        }
+        final boolean shouldHide = isPlayerNametagHidden(entityId);
+        final boolean hasServerPassenger = getPassenger(entityId) != -1;
+        final boolean hasSkull = playerNametagHiderEntities.containsKey(entityId);
+
+        if (shouldHide && !hasServerPassenger && !hasSkull) {
+            spawnNametagHiderEntity(entityId);
+        } else if ((!shouldHide || hasServerPassenger) && hasSkull) {
+            despawnNametagHiderEntity(entityId);
+        }
+    }
+
+    public void checkNametagVisbility(final String username) {
+        final GameProfileStorage profileStorage = user().get(GameProfileStorage.class);
+        final List<GameProfileStorage.GameProfile> profiles = profileStorage.get(username, false);
+
+        for (GameProfileStorage.GameProfile profile : profiles) {
+            final int entityId = getPlayerEntityId(profile.uuid);
+            if (entityId == -1) {
+                return;
+            }
+
+            checkNametagVisibility(entityId);
+        }
+    }
+
+    private boolean isPlayerNametagHidden(final int entityId) {
+        final UUID uuid = entityIdToUUID.get(entityId);
+        if (uuid == null) {
+            return false;
+        }
+        final GameProfileStorage profileStorage = user().get(GameProfileStorage.class);
+        final GameProfileStorage.GameProfile profile = profileStorage.get(uuid);
+        if (profile == null) {
+            return false;
+        }
+        return user().get(ScoreboardTracker.class).isNametagHidden(profile.name);
+    }
+
+    private int getNametagHiderEntityId(final int playerEntityId) {
+        return Integer.MAX_VALUE - 32000 - playerEntityId;
+    }
+
+    private void spawnNametagHiderEntity(final int playerEntityId) {
+        final int entityId = getNametagHiderEntityId(playerEntityId);
+        playerNametagHiderEntities.put(playerEntityId, entityId);
+
+        final List<EntityData> mobData = new ArrayList<>();
+        mobData.add(new EntityData(0, EntityDataTypes1_7_6_10.BYTE, (byte) 0x20));
+        mobData.add(new EntityData(16, EntityDataTypes1_7_6_10.BYTE, (byte) 0));
+
+        final PacketWrapper spawnMob = PacketWrapper.create(ClientboundPackets1_7_2_5.ADD_MOB, user());
+        spawnMob.write(Types.VAR_INT, entityId);
+        spawnMob.write(Types.UNSIGNED_BYTE, (short) EntityTypes1_8.EntityType.MAGMA_CUBE.getId());
+        spawnMob.write(Types.INT, 0); // X
+        spawnMob.write(Types.INT, 0); // Y
+        spawnMob.write(Types.INT, 0); // Z
+        spawnMob.write(Types.BYTE, (byte) 0); // Yaw
+        spawnMob.write(Types.BYTE, (byte) 0); // Pitch
+        spawnMob.write(Types.BYTE, (byte) 0); // Head yaw
+        spawnMob.write(Types.SHORT, (short) 0); // Velocity x
+        spawnMob.write(Types.SHORT, (short) 0); // Velocity y
+        spawnMob.write(Types.SHORT, (short) 0); // Velocity z
+        spawnMob.write(RewindTypes.ENTITY_DATA_LIST1_7, mobData);
+        spawnMob.scheduleSend(Protocol1_8To1_7_6_10.class);
+
+        final PacketWrapper attach = PacketWrapper.create(ClientboundPackets1_7_2_5.SET_ENTITY_LINK, user());
+        attach.write(Types.INT, entityId);
+        attach.write(Types.INT, playerEntityId);
+        attach.write(Types.BOOLEAN, false);
+        attach.scheduleSend(Protocol1_8To1_7_6_10.class);
+    }
+
+    private void despawnNametagHiderEntity(final int playerEntityId) {
+        if (!playerNametagHiderEntities.containsKey(playerEntityId)) return;
+        final int mobId = playerNametagHiderEntities.remove(playerEntityId);
+
+        final PacketWrapper despawn = PacketWrapper.create(ClientboundPackets1_7_2_5.REMOVE_ENTITIES, user());
+        despawn.write(Types.BYTE, (byte) 1);
+        despawn.write(Types.INT, mobId);
+        despawn.scheduleSend(Protocol1_8To1_7_6_10.class);
+    }
+
     public Int2ObjectMap<VirtualHologramEntity> getHolograms() {
         return holograms;
     }
 
+    public void setExtraHologramId(final int entityId, final int extraId) {
+        extraHologramIds.put(extraId, entityId);
+    }
+
+    public void removeExtraHologramId(int extraId) {
+        extraHologramIds.remove(extraId);
+    }
+
+    public int getHologramIdWithExtra(final int id) {
+        if (holograms.containsKey(id)) {
+            return id;
+        }
+        return extraHologramIds.getOrDefault(id, -1);
+    }
+
     public boolean isSpectator() {
         return clientEntityGameMode == 3;
     }

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/InventoryTracker.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -37,6 +37,7 @@ public class ScoreboardTracker extends StoredObject {
     private final HashMap<String, Byte> teamColors = new HashMap<>();
     private final HashSet<String> scoreTeamNames = new HashSet<>();
     private final HashMap<Byte, String> colorDependentSidebar = new HashMap<>();
+    private final HashMap<String, String> teamNameTagVisibilities = new HashMap<>();
     private String colorIndependentSidebar;
 
     public ScoreboardTracker(UserConnection user) {
@@ -63,6 +64,7 @@ public class ScoreboardTracker extends StoredObject {
         teams.remove(team);
         scoreTeams.remove(team);
         teamColors.remove(team);
+        teamNameTagVisibilities.remove(team);
     }
 
     public boolean teamExists(String team) {
@@ -98,6 +100,27 @@ public class ScoreboardTracker extends StoredObject {
         return Optional.empty();
     }
 
+    public void setTeamNameTagVisibility(String team, String visibility) {
+        teamNameTagVisibilities.put(team, visibility);
+    }
+
+    public String getTeamNameTagVisibility(String team) {
+        return teamNameTagVisibilities.getOrDefault(team, "always");
+    }
+
+    public boolean isNametagHidden(String username) {
+        for (Map.Entry<String, List<String>> entry : teams.entrySet()) {
+            if (entry.getValue().contains(username)) {
+                return "never".equalsIgnoreCase(teamNameTagVisibilities.getOrDefault(entry.getKey(), "always"));
+            }
+        }
+        return false;
+    }
+
+    public List<String> getTeamMembers(String team) {
+        return teams.getOrDefault(team, new ArrayList<>());
+    }
+
     public void addObjective(String name) {
         objectives.add(name);
     }
@@ -117,37 +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/storage/WorldBorderEmulator.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -18,21 +18,25 @@
 package com.viaversion.viarewind.protocol.v1_9to1_8;
 
 import com.viaversion.viabackwards.api.BackwardsProtocol;
-import com.viaversion.viarewind.protocol.v1_9to1_8.data.RewindMappingData1_8;
+import com.viaversion.viarewind.api.data.RewindMappingData;
+import com.viaversion.viarewind.protocol.v1_9to1_8.provider.InventoryProvider;
 import com.viaversion.viarewind.protocol.v1_9to1_8.rewriter.BlockItemPacketRewriter1_9;
 import com.viaversion.viarewind.protocol.v1_9to1_8.rewriter.EntityPacketRewriter1_9;
 import com.viaversion.viarewind.protocol.v1_9to1_8.rewriter.PlayerPacketRewriter1_9;
 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;
@@ -50,7 +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) {
@@ -60,7 +64,7 @@ public class Protocol1_9To1_8 extends BackwardsProtocol<ClientboundPackets1_9, C
         }
     };
 
-    public static final RewindMappingData1_8 MAPPINGS = new RewindMappingData1_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);
@@ -79,25 +83,30 @@ 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
     public void register(ViaProviders providers) {
+        providers.register(InventoryProvider.class, new InventoryProvider());
+
         Via.getManager().getScheduler().scheduleRepeating(new LevitationUpdateTask(), 0L, 50L, TimeUnit.MILLISECONDS);
         Via.getManager().getScheduler().scheduleRepeating(new CooldownIndicatorTask(), 0L, 50L, TimeUnit.MILLISECONDS);
     }
 
     @Override
-    public RewindMappingData1_8 getMappingData() {
+    public RewindMappingData getMappingData() {
         return MAPPINGS;
     }
 

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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/data/EffectIdMappings1_8.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/data/EntityDataIndex1_8.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/data/PotionIdMappings1_8.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/data/RewindMappingData1_8.java

@@ -1,48 +0,0 @@
-/*
- * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 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.viarewind.api.data.RewindMappingDataLoader;
-import com.viaversion.viaversion.libs.fastutil.objects.ObjectArrayList;
-import com.viaversion.viaversion.libs.fastutil.objects.ObjectList;
-import com.viaversion.viaversion.libs.gson.JsonArray;
-import com.viaversion.viaversion.libs.gson.JsonElement;
-
-public final class RewindMappingData1_8 extends com.viaversion.viarewind.api.data.RewindMappingData {
-
-    private final ObjectList<String> sounds = new ObjectArrayList<>();
-
-    public RewindMappingData1_8() {
-        super("1.9.4", "1.8");
-    }
-
-    @Override
-    protected void loadExtras(CompoundTag data) {
-        super.loadExtras(data);
-
-        final JsonArray sounds = RewindMappingDataLoader.INSTANCE.loadData("sounds-1.9.json").getAsJsonArray("sounds");
-        for (final JsonElement sound : sounds) {
-            this.sounds.add(sound.getAsString());
-        }
-    }
-
-    public String soundName(final int soundId) {
-        return sounds.get(soundId);
-    }
-}

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/provider/InventoryProvider.java

@@ -0,0 +1,29 @@
+/*
+ * 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.provider;
+
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.platform.providers.Provider;
+
+public class InventoryProvider implements Provider {
+
+    public boolean hasElytra(final UserConnection connection) {
+        return false;
+    }
+
+}

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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 -> {
@@ -118,7 +118,7 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
                         wrapper.set(Types.BYTE, 1, yaw);
 
                         int y = wrapper.get(Types.INT, 1);
-                        y += 10;
+                        y += 6;
                         wrapper.set(Types.INT, 1, y);
                     }
 
@@ -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();
@@ -360,13 +373,13 @@ 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;
                         wrapper.set(Types.BYTE, 0, yaw);
                         int y = wrapper.get(Types.INT, 1);
-                        y += 10;
+                        y += 6;
                         wrapper.set(Types.INT, 1, y);
                     }
                 });
@@ -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);
             }
@@ -399,9 +412,11 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
             public void register() {
                 map(Types.VAR_INT); // Entity id
                 handler(wrapper -> {
-                    // todo check if this is correct for the own player
+                    // 1.8 clients write their own equipment to armorInventory[slot] without the -1 offset,
+                    // shifting armor up one slot; the window 0 set slot packets already carry it.
+                    final int entityId = wrapper.get(Types.VAR_INT, 0);
                     int slot = wrapper.read(Types.VAR_INT);
-                    if (slot == 1) {
+                    if (slot == 1 || entityId == wrapper.user().getEntityTracker(protocol).clientEntityId()) {
                         wrapper.cancel();
                     } else if (slot > 1) {
                         slot -= 1;
@@ -416,7 +431,7 @@ 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 +459,19 @@ 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() {
@@ -457,14 +485,26 @@ 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;
                         wrapper.set(Types.BYTE, 0, yaw);
 
                         int y = wrapper.get(Types.INT, 1);
-                        y += 10;
+                        y += 6;
                         wrapper.set(Types.INT, 1, y);
                     }
                     tracker.resetEntityOffset(entityId);
@@ -475,7 +515,7 @@ 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 +562,7 @@ 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);
@@ -535,16 +575,62 @@ public class EntityPacketRewriter1_9 extends VREntityRewriter<ClientboundPackets
     protected void registerRewrites() {
         // Handle new entities
         mapEntityTypeWithData(EntityTypes1_9.EntityType.SHULKER, EntityTypes1_9.EntityType.MAGMA_CUBE).plainName();
-        mapEntityTypeWithData(EntityTypes1_9.EntityType.SHULKER_BULLET, EntityTypes1_9.EntityType.WITCH).plainName();
+        mapObjectType(EntityTypes1_9.ObjectType.SHULKER_BULLET, EntityTypes1_9.ObjectType.WITHER_SKULL, -1).plainName();
 
         // Entity data rewrite
         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 +640,10 @@ 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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -21,14 +21,17 @@ 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;
 import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.minecraft.BlockPosition;
 import com.viaversion.viaversion.api.minecraft.ClientWorld;
@@ -41,7 +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;
@@ -51,6 +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) {
@@ -105,6 +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() {
@@ -131,8 +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);
@@ -141,7 +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) {
@@ -157,18 +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);
                 });
             }
         });
@@ -178,11 +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();
                     }
@@ -201,7 +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
 
@@ -271,7 +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();
                     }
@@ -289,7 +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;
                     }
 
@@ -309,7 +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;
                     }
 
@@ -331,13 +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);
@@ -409,10 +452,11 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 map(Types.VAR_INT); // Action parameter
                 handler(wrapper -> {
                     final PlayerPositionTracker tracker = wrapper.user().get(PlayerPositionTracker.class);
+                    final InventoryProvider provider = Via.getManager().getProviders().get(InventoryProvider.class);
                     final int action = wrapper.get(Types.VAR_INT, 1);
                     if (action == 6) { // Jump with horse
                         wrapper.set(Types.VAR_INT, 1, 7);
-                    } else if (action == 0 && !tracker.isOnGround()) { // Start sneaking
+                    } else if (action == 0 && provider.hasElytra(wrapper.user()) && !tracker.isOnGround()) { // Start sneaking
                         final PacketWrapper elytra = PacketWrapper.create(ServerboundPackets1_9.PLAYER_COMMAND, wrapper.user());
                         elytra.write(Types.VAR_INT, wrapper.get(Types.VAR_INT, 0));
                         elytra.write(Types.VAR_INT, 8);
@@ -427,7 +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) {
@@ -444,7 +488,7 @@ public class PlayerPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
                 map(Types.BLOCK_POSITION1_8); // Position
                 handler(wrapper -> {
                     for (int i = 0; i < 4; i++) {
-                        final JsonElement json = wrapper.read(RewindTypes.SIGN_COMPONENT);
+                        final JsonElement json = wrapper.read(Types.COMPONENT);
                         if (!json.isJsonPrimitive()) {
                             throw new IllegalStateException("Invalid sign text: " + StringUtil.forLogging(json));
                         }
@@ -477,7 +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));
@@ -521,7 +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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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
@@ -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;
@@ -251,11 +279,11 @@ public class WorldPacketRewriter1_9 extends RewriterBase<Protocol1_9To1_8> {
             public void register() {
                 handler(wrapper -> {
                     final int soundId = wrapper.read(Types.VAR_INT);
-                    final String soundName = protocol.getMappingData().soundName(soundId);
-                    if (soundName == null) {
+                    final int mappedSoundId = protocol.getMappingData().getFullSoundMappings().getNewId(soundId);
+                    if (mappedSoundId == -1) {
                         wrapper.cancel();
                     } else {
-                        wrapper.write(Types.STRING, protocol.getMappingData().getMappedNamedSound(soundName));
+                        wrapper.write(Types.STRING, protocol.getMappingData().getFullSoundMappings().mappedIdentifier(mappedSoundId));
                     }
                 });
                 read(Types.VAR_INT); // Sound category
@@ -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/BlockPlaceDestroyTracker.java

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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

@@ -1,6 +1,6 @@
 /*
  * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
- * Copyright (C) 2018-2025 ViaVersion and contributors
+ * 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

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();
+            }
+        }
+    }
+}