diff --git a/.github/workflows/deploy_snapshot.yml b/.github/workflows/deploy_snapshot.yml
index 735d77a6c..32de396cc 100644
--- a/.github/workflows/deploy_snapshot.yml
+++ b/.github/workflows/deploy_snapshot.yml
@@ -15,7 +15,8 @@ on:
     types: [ trigger_after_upstream_deploy ]
 
 env:
-  GRADLE_VERSION: 7.6 # Gradle version used
+  GRADLE_VERSION: 8.5 # Gradle version used
+  JAVA_VERSION: 21    # Java version used
   GRADLE_CLI_OPTS: "-Pci --build-cache -PgenTR=false -PgenTagging=true --refresh-dependencies " # CLI options passed to Gradle
   GRADLE_BUILD_ACTION_CACHE_KEY_JOB: "test-cache-${{ github.head_ref }}.${{ github.sha }}"
 
@@ -29,6 +30,11 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: ${{ env.JAVA_VERSION }}
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
@@ -45,6 +51,11 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: ${{ env.JAVA_VERSION }}
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
diff --git a/.github/workflows/test_branch.yml b/.github/workflows/test_branch.yml
index 5b3f3fb7a..451191296 100644
--- a/.github/workflows/test_branch.yml
+++ b/.github/workflows/test_branch.yml
@@ -14,7 +14,8 @@ on:
     types: [opened, synchronize]
 
 env:
-  GRADLE_VERSION: 7.6 # Gradle version used
+  GRADLE_VERSION: 8.5 # Gradle version used
+  JAVA_VERSION: 21    # Java version used
   GRADLE_CLI_OPTS: "-Pci --build-cache  -PgenTR=false -PgenTagging=true --refresh-dependencies " # CLI options passed to Gradle
   GRADLE_BUILD_ACTION_CACHE_KEY_JOB: "test-cache-${{ github.head_ref }}.${{ github.sha }}"
 
@@ -30,6 +31,11 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: ${{ env.JAVA_VERSION }}
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 709a25970..b8b48daba 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,6 @@
 # (c) https://github.com/MontiCore/monticore
 
-image: registry.git.rwth-aachen.de/monticore/container-registry/gradle:7.6.4-jdk11
+image: registry.git.rwth-aachen.de/monticore/container-registry/gradle:8.5-jdk21
 
 variables:
   GRADLE_OPTS: "-Dorg.gradle.daemon=false"
diff --git a/README.md b/README.md
index e245d4a8f..b9bb96f87 100644
--- a/README.md
+++ b/README.md
@@ -116,7 +116,7 @@ processing models, including:
 * computing the semantic difference of 2 CDs, and
 * merging 2 CDs (iff the result is semantically sound)
 
-The requirements for building and using the CD tool are that Java 11, Git, 
+The requirements for building and using the CD tool are that Java 21, Git, 
 and Gradle are installed and available for use (e.g., in bash). 
 
 ### Downloading the Latest Version of the Tool
@@ -186,8 +186,8 @@ As alternative to a download,
 it is possible to build an executable JAR of the tool from the source files
 located in GitHub.
 Make sure you have installed the following dependencies:
-* Java 11 or 17 (check it with java -version)
-* Gradle 7.6.4 (check it with gradle --version)
+* Java 21 (check it with java -version)
+* Gradle 8.5 (check it with gradle --version)
 
 In order to build an executable Jar of the tool with
 Bash from the source files available in GitHub, execute the following commands.
diff --git a/build.gradle b/build.gradle
index 937c12119..31b433f20 100644
--- a/build.gradle
+++ b/build.gradle
@@ -4,11 +4,13 @@ import org.gradle.api.tasks.testing.logging.TestLogEvent
 /* (c) https://github.com/MontiCore/monticore */
 
 plugins {
+  id 'java'
   id "maven-publish"
   id "io.github.themrmilchmann.ecj" version "0.2.0" apply(false) // Eclipse compiler as it's much faster than javac
   id "de.se_rwth.codestyle" version "$mc_version"
 }
 
+
 description = "CD4Analysis"
 buildDir = file("$projectDir/target")
 
@@ -24,7 +26,7 @@ ext {
   junit_platform_version = "1.14.1"
   freemarker_version = "2.3.31"
   javaparser_version = "3.14.11"
-  mockito_version = "3.11.1"
+  mockito_version = "5.11.0"
   logback_version = "1.2.3"
   apache_commons_version = '4.4'
 }
@@ -37,12 +39,17 @@ repositories {
 }
 
 subprojects {
+
   apply plugin: 'java-library'
   apply plugin: 'io.github.themrmilchmann.ecj'
   apply plugin: 'maven-publish'
   apply plugin: 'de.se_rwth.codestyle'
 
-  sourceCompatibility = JavaVersion.VERSION_11
+    ecj {
+        compilerVersion = "3.43.0"
+    }
+
+  sourceCompatibility = JavaVersion.VERSION_21
 
   allprojects {
     group = "de.monticore.lang.cd4analysis"
@@ -105,7 +112,7 @@ subprojects {
   }
   java {
     toolchain {
-      languageVersion = JavaLanguageVersion.of(11)
+      languageVersion = JavaLanguageVersion.of(21)
     }
   }
 }
diff --git a/cdtool/build.gradle b/cdtool/build.gradle
index 93961e995..f33e646ea 100644
--- a/cdtool/build.gradle
+++ b/cdtool/build.gradle
@@ -1,6 +1,6 @@
 /* (c) https://github.com/MontiCore/monticore */
 plugins {
-  id "com.github.johnrengelman.shadow" version "$shadow_plugin_version"
+    id 'com.gradleup.shadow' version "$shadow_plugin_version"
 }
 
 description = "CD4Analysis: Tool"
diff --git a/cdtool/cdgradle/src/test/java/de/monticore/cdgen/CDGenGradlePluginTest.java b/cdtool/cdgradle/src/test/java/de/monticore/cdgen/CDGenGradlePluginTest.java
index 948c07cb4..d6ac7f4f0 100644
--- a/cdtool/cdgradle/src/test/java/de/monticore/cdgen/CDGenGradlePluginTest.java
+++ b/cdtool/cdgradle/src/test/java/de/monticore/cdgen/CDGenGradlePluginTest.java
@@ -19,30 +19,18 @@
 import org.gradle.testkit.runner.GradleRunner;
 import org.gradle.testkit.runner.TaskOutcome;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 public class CDGenGradlePluginTest {
   
   @TempDir
   File testProjectDir;
   
-  @Test
-  public void testCDGen_v7_4_2() throws IOException {
-    testCDGen("7.4.2");
-  }
-  
-  @Test
-  public void testCDGen_v8_0_1() throws IOException {
-    this.testCDGen("8.0.1");
-  }
-  
-  @Test
-  public void testCDGen_v8_7() throws IOException {
-    this.testCDGen("8.7");
-  }
-  
-  void testCDGen(String version) throws IOException {
+  @ParameterizedTest
+  @ValueSource(strings = { "8.5", "8.7", "8.14" })
+  public void testCDGen(String version) throws IOException {
     FileUtils.copyDirectory(new File("src/test/resources/cdgradle-it"), testProjectDir);
     
     BuildResult result = GradleRunner.create().withPluginClasspath().withGradleVersion(version)
@@ -77,21 +65,6 @@ void testCDGen(String version) throws IOException {
     CD4CodeMill.reset();
   }
   
-  @Test
-  public void testCDGenOwnDecorator_v7_4_2() throws IOException {
-    this.testCDGenOwnDecorator("7.4.2");
-  }
-  
-  @Test
-  public void testCDGenOwnDecorator_v8_0_1() throws IOException {
-    this.testCDGenOwnDecorator("8.0.1");
-  }
-  
-  @Test
-  public void testCDGenOwnDecorator_v8_7() throws IOException {
-    this.testCDGenOwnDecorator("8.7");
-  }
-  
   /**
    * Test the CDGenPlugin with a decorator written in a custom sourceSet and a custom config
    * template
@@ -99,7 +72,9 @@ public void testCDGenOwnDecorator_v8_7() throws IOException {
    * @param version gradle version
    * @throws IOException in case of errors
    */
-  void testCDGenOwnDecorator(String version) throws IOException {
+  @ParameterizedTest
+  @ValueSource(strings = { "8.5", "8.7", "8.14" })
+  public void testCDGenOwnDecorator(String version) throws IOException {
     FileUtils.copyDirectory(new File("src/test/resources/cdgradle-it"), testProjectDir);
     
     BuildResult result = GradleRunner.create().withPluginClasspath().withGradleVersion(version)
diff --git a/gradle.properties b/gradle.properties
index e53485750..be5d1893f 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ repo=https://nexus.se.rwth-aachen.de/content/groups/public
 version=7.9.0-SNAPSHOT
 mc_version=7.9.0-SNAPSHOT
 commons_version=7.9.0-SNAPSHOT
-shadow_plugin_version=7.1.2
+shadow_plugin_version=8.3.9
 useLocalRepo=false
 org.gradle.jvmargs=-Xmx4096m
 org.gradle.parallel=true
diff --git a/language-server/build.gradle b/language-server/build.gradle
index 0861258e9..67feba08b 100644
--- a/language-server/build.gradle
+++ b/language-server/build.gradle
@@ -9,7 +9,7 @@ plugins {
 group 'de.monticore.lang'
 version mc_version
 
-sourceCompatibility = JavaVersion.VERSION_11
+sourceCompatibility = JavaVersion.VERSION_21
 
 repositories {
   mavenCentral()
diff --git a/symtabdefinitiontool/build.gradle b/symtabdefinitiontool/build.gradle
index 360e1f3eb..3ba11d449 100644
--- a/symtabdefinitiontool/build.gradle
+++ b/symtabdefinitiontool/build.gradle
@@ -1,6 +1,6 @@
 /* (c) https://github.com/MontiCore/monticore */
 plugins {
-  id "com.github.johnrengelman.shadow" version "$shadow_plugin_version"
+    id 'com.gradleup.shadow' version "$shadow_plugin_version"
 }
 
 description = "SymTabDefinition: Tool"
diff --git a/trafo-library/build.gradle b/trafo-library/build.gradle
index a14c819ad..29d075f3d 100644
--- a/trafo-library/build.gradle
+++ b/trafo-library/build.gradle
@@ -10,7 +10,7 @@ import de.monticore.MontiTransExec
 
 group = "de.monticore.lang"
 description = "trafo-library"
-sourceCompatibility = JavaVersion.VERSION_11
+sourceCompatibility = JavaVersion.VERSION_21
 buildDir = file("$projectDir/target")