diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 534780374..694d459e3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,11 +18,11 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Setup Java 21
+      - name: Setup Java 17
         uses: actions/setup-java@v3
         with:
           distribution: temurin
-          java-version: 21
+          java-version: 17
 
       - name: Install Rust Toolchain
         run: rustup update && rustup target add armv7-linux-androideabi aarch64-linux-android i686-linux-android x86_64-linux-android && rustup component add rustfmt clippy
diff --git a/.github/workflows/releases.yml b/.github/workflows/releases.yml
index 69a5c07cd..083acefd6 100644
--- a/.github/workflows/releases.yml
+++ b/.github/workflows/releases.yml
@@ -15,11 +15,11 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Setup Java 21
+      - name: Setup Java 17
         uses: actions/setup-java@v3
         with:
           distribution: temurin
-          java-version: 21
+          java-version: 17
 
       - name: Install Rust Toolchain
         run: rustup update && rustup target add armv7-linux-androideabi aarch64-linux-android i686-linux-android x86_64-linux-android
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 69c3acc8e..c528c8f72 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -276,7 +276,7 @@ dependencies {
 }
 
 kotlin {
-    jvmToolchain(21)
+    jvmToolchain(17)
 }
 
 ksp {
diff --git a/build.gradle.kts b/build.gradle.kts
index 429cf9ff1..81a014ce7 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -9,3 +9,13 @@ plugins {
     alias(libs.plugins.rustAndroidPlugin) apply false
     alias(libs.plugins.composeCompilerReportGenerator) apply false
 }
+
+tasks.register("Delete", Delete::class) {
+    delete(rootProject.layout.buildDirectory)
+}
+
+buildscript {
+    dependencies {
+        classpath(libs.r8)
+    }
+}
diff --git a/gradle.properties b/gradle.properties
index b88f893b2..bfddba75b 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -21,5 +21,6 @@ org.gradle.caching=true
 android.useAndroidX=true
 android.enableAppCompileTimeRClass=true
 android.experimental.enableNewResourceShrinker.preciseShrinking=true
+android.experimental.lint.version=8.3.0-alpha09
 android.lint.useK2Uast=true
 kotlin.experimental.tryK2=true
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 6b22d8de3..79fe956c0 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,6 +1,7 @@
 [versions]
 aboutlibraries = "10.9.1"
-agp = "8.3.0-alpha09"
+agp = "8.1.2"
+android-tools-r8 = "8.3.12-dev"
 androidx-activity = "1.8.0"
 androidx-appcompat = "1.6.1"
 androidx-biometric = "1.2.0-alpha05"
@@ -121,6 +122,8 @@ okio-jvm = { module = "com.squareup.okio:okio-jvm", version.ref = "okio" }
 
 photoview = "com.github.chrisbanes:PhotoView:2.3.0"
 
+r8 = { module = "com.android.tools:r8", version.ref = "android-tools-r8" }
+
 rikkax-core = "dev.rikka.rikkax.core:core-ktx:1.4.1"
 rikkax-insets = "dev.rikka.rikkax.insets:insets:1.3.0"
 rikkax-layoutinflater = "dev.rikka.rikkax.layoutinflater:layoutinflater:1.3.0"
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 103108a90..8c28e8012 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -3,6 +3,7 @@ pluginManagement {
         gradlePluginPortal()
         google()
         mavenCentral()
+        maven("https://storage.googleapis.com/r8-releases/raw")
     }
 }