diff --git a/.github/workflows/deploy-release.yml b/.github/workflows/deploy-release.yml
index 281fc15..745445a 100644
--- a/.github/workflows/deploy-release.yml
+++ b/.github/workflows/deploy-release.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
 
       - name: Deploy release
         env:
diff --git a/.github/workflows/verify-pr.yml b/.github/workflows/verify-pr.yml
index 42af676..1ff7adf 100644
--- a/.github/workflows/verify-pr.yml
+++ b/.github/workflows/verify-pr.yml
@@ -16,7 +16,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
 
       - name: Check app
         run: ./gradlew check
@@ -37,7 +37,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
diff --git a/android-tests/build.gradle.kts b/android-tests/build.gradle.kts
index b96243b..82e90a2 100644
--- a/android-tests/build.gradle.kts
+++ b/android-tests/build.gradle.kts
@@ -7,6 +7,12 @@ val androidMinSdk: Int by rootProject.extra
 val androidTargetSdk: Int by rootProject.extra
 val androidCompileSdk: Int by rootProject.extra
 
+java {
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(21)
+	}
+}
+
 android {
 	namespace = "com.svenjacobs.reveal.android.tests"
 	compileSdk = androidCompileSdk
diff --git a/convention-plugins/src/main/kotlin/convention.multiplatform.gradle.kts b/convention-plugins/src/main/kotlin/convention.multiplatform.gradle.kts
index 1aac678..4fd9079 100644
--- a/convention-plugins/src/main/kotlin/convention.multiplatform.gradle.kts
+++ b/convention-plugins/src/main/kotlin/convention.multiplatform.gradle.kts
@@ -5,6 +5,12 @@ plugins {
 
 val baseName: String by extra
 
+java {
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(21)
+	}
+}
+
 kotlin {
 	applyDefaultHierarchyTemplate()
 
diff --git a/reveal-compat-android/build.gradle.kts b/reveal-compat-android/build.gradle.kts
index 2c72ca4..fe93807 100644
--- a/reveal-compat-android/build.gradle.kts
+++ b/reveal-compat-android/build.gradle.kts
@@ -5,6 +5,12 @@ plugins {
 	id("convention.publication")
 }
 
+java {
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(21)
+	}
+}
+
 val publicationName by extra { "Reveal (Compat Android)" }
 
 val androidMinSdk: Int by rootProject.extra