diff --git a/.gitpod/Dockerfile b/.gitpod/Dockerfile
index 28f5ac5af..13a3db3fc 100644
--- a/.gitpod/Dockerfile
+++ b/.gitpod/Dockerfile
@@ -2,8 +2,8 @@
 # specifically tailored for building Jenkins plugins. It includes the installation of Maven,
 # cloning of two specific Jenkins plugin repositories, and building these plugins using Maven.
 
-# Start from a base image that includes JDK 17 and Git. This serves as the foundation for the development environment.
-FROM gitpod/workspace-java-17
+# Start from a base image that includes JDK 21 and Git. This serves as the foundation for the development environment.
+FROM gitpod/workspace-java-21
 
 # Define the versions of the JDKs to install. This is used by the `sdk install java` command to install the specified JDK.
 ENV JDK8_PACKAGE=8.0.462-tem
diff --git a/Jenkinsfile b/Jenkinsfile
index 4fbd6ff82..438a9b51a 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -5,5 +5,5 @@ buildPlugin(
     useContainerAgent: false,
     configurations: [
         [platform: 'linux', jdk: 21],
-        [platform: 'windows', jdk: 17],
+        [platform: 'windows', jdk: 21],
  ])
diff --git a/README.md b/README.md
index 1da17d516..b6493a829 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ Learn more at [this project page](https://www.jenkins.io/projects/gsoc/2024/proj
 
 ### Requirements
 - Maven version 3.9.7 or later, or mvnd
-- Java 17 or Java 21 ([Eclipse Temurin](https://adoptium.net/temurin/releases) recommended)
+- Java 21 ([Eclipse Temurin](https://adoptium.net/temurin/releases) recommended)
 
 ### Build
 
diff --git a/plugin-modernizer-cli/src/test/java/io/jenkins/tools/pluginmodernizer/cli/CommandLineITCase.java b/plugin-modernizer-cli/src/test/java/io/jenkins/tools/pluginmodernizer/cli/CommandLineITCase.java
index 22fe43bd8..b46e437ff 100644
--- a/plugin-modernizer-cli/src/test/java/io/jenkins/tools/pluginmodernizer/cli/CommandLineITCase.java
+++ b/plugin-modernizer-cli/src/test/java/io/jenkins/tools/pluginmodernizer/cli/CommandLineITCase.java
@@ -680,6 +680,7 @@ private InvocationRequest buildRequest(String args, Path logFile) {
             properties.put("set.changelist", "true");
         }
         properties.put("exec.executable", javaHome.resolve("bin/java").toString());
+        LOG.debug("Using java executable: {}", properties.get("exec.executable"));
         properties.put("test.cliArgs", args);
         request.setProperties(properties);
 
diff --git a/plugin-modernizer-core/pom.xml b/plugin-modernizer-core/pom.xml
index 716d66c33..5b41904c1 100644
--- a/plugin-modernizer-core/pom.xml
+++ b/plugin-modernizer-core/pom.xml
@@ -147,12 +147,6 @@
     <dependency>
       <groupId>org.openrewrite.recipe</groupId>
       <artifactId>rewrite-migrate-java</artifactId>
-      <exclusions>
-        <exclusion>
-          <groupId>org.openrewrite</groupId>
-          <artifactId>rewrite-java-21</artifactId>
-        </exclusion>
-      </exclusions>
     </dependency>
     <dependency>
       <groupId>org.openrewrite.recipe</groupId>
diff --git a/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/impl/PluginModernizer.java b/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/impl/PluginModernizer.java
index 2bd626cf0..9d81e1e37 100644
--- a/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/impl/PluginModernizer.java
+++ b/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/impl/PluginModernizer.java
@@ -159,6 +159,7 @@ public void start() {
         LOG.debug("Plugin Health Score Url: {}", config.getPluginHealthScore());
         LOG.debug("Installation Stats Url: {}", config.getPluginStatsInstallations());
         LOG.debug("Cache Path: {}", config.getCachePath());
+        LOG.debug("Java Version: {}", getJavaVersion());
         LOG.debug("Maven Home: {}", config.getMavenHome());
         LOG.debug("Maven Local Repository: {}", config.getMavenLocalRepo());
         LOG.debug("Dry Run: {}", config.isDryRun());
@@ -237,7 +238,7 @@ private void process(Plugin plugin) {
             plugin.checkoutBranch(ghService);
 
             // Minimum JDK to run openrewrite
-            plugin.withJDK(JDK.JAVA_17);
+            plugin.withJDK(JDK.JAVA_21);
 
             // Collect metadata and move metadata from the target directory of the plugin to the common cache
             if (!plugin.hasMetadata() || config.isFetchMetadataOnly()) {
@@ -348,7 +349,7 @@ private void process(Plugin plugin) {
 
             // Recollect metadata after modernization
             if (!config.isFetchMetadataOnly()) {
-                plugin.withJDK(JDK.JAVA_17);
+                plugin.withJDK(JDK.JAVA_21);
                 plugin.clean(mavenInvoker);
                 collectMetadata(plugin, false);
                 LOG.debug(
@@ -416,7 +417,7 @@ private void process(Plugin plugin) {
      */
     private void collectMetadata(Plugin plugin, boolean retryAfterFirstCompile) {
         LOG.trace("Collecting metadata for plugin {}... Please be patient", plugin.getName());
-        plugin.withJDK(JDK.JAVA_17);
+        plugin.withJDK(JDK.JAVA_21);
         try {
             plugin.collectMetadata(mavenInvoker);
             if (plugin.hasErrors()) {
@@ -435,7 +436,7 @@ private void collectMetadata(Plugin plugin, boolean retryAfterFirstCompile) {
                             plugin.getName());
                     plugin.raiseLastError();
                 }
-                plugin.withJDK(JDK.JAVA_17);
+                plugin.withJDK(JDK.JAVA_21);
                 plugin.collectMetadata(mavenInvoker);
             } else {
                 LOG.info("Failed to collect metadata for plugin {}. Not retrying.", plugin.getName());
@@ -539,7 +540,7 @@ private JDK verifyPlugin(Plugin plugin) {
         // Determine the JDK
         JDK jdk;
         if (metadata.getJdks() == null || metadata.getJdks().isEmpty()) {
-            jdk = JDK.JAVA_17;
+            jdk = JDK.JAVA_21;
             LOG.info(
                     "No JDKs found in metadata for plugin {}. Using same JDK as rewrite for verification",
                     plugin.getName());
diff --git a/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/model/Plugin.java b/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/model/Plugin.java
index d9155c8e1..a1743b2cf 100644
--- a/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/model/Plugin.java
+++ b/plugin-modernizer-core/src/main/java/io/jenkins/tools/pluginmodernizer/core/model/Plugin.java
@@ -788,7 +788,7 @@ public void collectMetadata(MavenInvoker maven) {
      * @param maven The maven invoker instance
      */
     public void runOpenRewrite(MavenInvoker maven) {
-        withJDK(JDK.JAVA_17);
+        withJDK(JDK.JAVA_21);
         if (config.isFetchMetadataOnly()) {
             LOG.info("Skipping OpenRewrite recipe application for plugin {} as only metadata is required", name);
             return;
diff --git a/pom.xml b/pom.xml
index 13f4df84a..c9a59d831 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,6 +36,7 @@
     <!-- Reproducible builds -->
     <project.build.outputTimestamp>2024-01-01T00:00:00Z</project.build.outputTimestamp>
 
+    <maven.compiler.release>21</maven.compiler.release>
     <maven.compiler.source>21</maven.compiler.source>
     <maven.compiler.target>21</maven.compiler.target>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -391,8 +392,8 @@
               <configuration>
                 <rules>
                   <requireJavaVersion>
-                    <version>17,21</version>
-                    <message>Project requires Java 17 or Java 21</message>
+                    <version>21</version>
+                    <message>Project Java 21</message>
                   </requireJavaVersion>
                 </rules>
               </configuration>