diff --git a/.github/workflows/buildpack-integration-test.yml b/.github/workflows/buildpack-integration-test.yml
index 41182ce3..c97377e7 100644
--- a/.github/workflows/buildpack-integration-test.yml
+++ b/.github/workflows/buildpack-integration-test.yml
@@ -14,7 +14,7 @@ on:
 permissions: read-all
 
 jobs:
-  java11-buildpack-test:
+  java21-buildpack-test:
     uses: GoogleCloudPlatform/functions-framework-conformance/.github/workflows/buildpack-integration-test.yml@main
     with:
       http-builder-source: '/tmp/tests/conformance'
@@ -22,8 +22,8 @@ jobs:
       cloudevent-builder-source: '/tmp/tests/conformance'
       cloudevent-builder-target: 'com.google.cloud.functions.conformance.CloudEventsConformanceFunction'
       prerun: 'invoker/conformance/prerun.sh'
-      builder-runtime: 'java11'
-      builder-runtime-version: '11'
+      builder-runtime: 'java21'
+      builder-runtime-version: '21'
       builder-url: gcr.io/serverless-runtimes/google-22-full/builder/java:latest
   java17-buildpack-test:
     uses: GoogleCloudPlatform/functions-framework-conformance/.github/workflows/buildpack-integration-test.yml@main
diff --git a/.github/workflows/conformance.yaml b/.github/workflows/conformance.yaml
index 9b03a3c6..074d8c14 100644
--- a/.github/workflows/conformance.yaml
+++ b/.github/workflows/conformance.yaml
@@ -14,7 +14,8 @@ jobs:
     strategy:
       matrix:
         java: [
-          11.x,
+          17.x,
+          21.x
         ]
     steps:
     - name: Harden Runner
diff --git a/.github/workflows/lint.yaml b/.github/workflows/lint.yaml
index 6cc5a37b..3a5860de 100644
--- a/.github/workflows/lint.yaml
+++ b/.github/workflows/lint.yaml
@@ -24,7 +24,7 @@ jobs:
     - name: Set up JDK
       uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # v4.7.1
       with:
-        java-version: 11.x
+        java-version: 17.x
         distribution: temurin
     - name: Build API with Maven
       run: (cd functions-framework-api/ && mvn install)
diff --git a/.github/workflows/unit.yaml b/.github/workflows/unit.yaml
index 2826605a..2ddc0a5c 100644
--- a/.github/workflows/unit.yaml
+++ b/.github/workflows/unit.yaml
@@ -13,9 +13,8 @@ jobs:
     strategy:
       matrix:
         java: [
-          11.x,
           17.x,
-          21-ea
+          21.x
         ]
     steps:
     - name: Harden Runner
@@ -37,4 +36,4 @@ jobs:
     - name: Build with Maven
       run: (cd functions-framework-api/ && mvn install)
     - name: Test
-      run: (cd invoker/ && mvn test)
\ No newline at end of file
+      run: (cd invoker/ && mvn test)
diff --git a/.kokoro/release.sh b/.kokoro/release.sh
index 8e1b30b0..89d7ebcd 100644
--- a/.kokoro/release.sh
+++ b/.kokoro/release.sh
@@ -64,7 +64,7 @@ fi
 echo "pwd=$(pwd)"
 
 # Make sure `JAVA_HOME` is set and using jdk11.
-export JAVA_HOME=/usr/lib/jvm/java-1.11.0-openjdk-amd64
+export JAVA_HOME=/usr/lib/jvm/java-1.17.0-openjdk-amd64
 echo "JAVA_HOME=$JAVA_HOME"
 mvn clean deploy -B -q \
   -P sonatype-oss-release \
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f7e4114c..5d18935a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -38,15 +38,15 @@ This project is divided into multiple packages, primarily:
   - `function-maven-plugin` - The Maven plugin for building functions
   - `conformance` - A set of functions used for conformance testing
 
-### Setup JDK 11 / 17
+### Setup JDK 17 / 21
 
-Install JDK 11 and 17. One way to install these is through [SDK man](https://sdkman.io/).
+Install JDK 17 and 21. One way to install these is through [SDK man](https://sdkman.io/).
 
 ```sh
-sdk install java 11.0.2-open
 sdk install java 17-open
+sdk install java 21-open
 sdk use java 17-open
-sdk use java 11.0.2-open
+sdk use java 21-open
 ```
 
 Verify Java version with:
diff --git a/function-maven-plugin/pom.xml b/function-maven-plugin/pom.xml
index a2e96114..657ce775 100644
--- a/function-maven-plugin/pom.xml
+++ b/function-maven-plugin/pom.xml
@@ -47,8 +47,8 @@
   </licenses>
 
   <properties>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
   </properties>
 
   <dependencies>
diff --git a/function-maven-plugin/src/main/java/com/google/cloud/functions/plugin/DeployFunction.java b/function-maven-plugin/src/main/java/com/google/cloud/functions/plugin/DeployFunction.java
index d0067ded..08bff714 100644
--- a/function-maven-plugin/src/main/java/com/google/cloud/functions/plugin/DeployFunction.java
+++ b/function-maven-plugin/src/main/java/com/google/cloud/functions/plugin/DeployFunction.java
@@ -98,13 +98,13 @@ public class DeployFunction extends CloudSdkMojo {
    * Runtime in which to run the function.
    *
    * <p>Required when deploying a new function; optional when updating an existing function. Default
-   * to Java11.
+   * to Java17.
    */
   @Parameter(
       alias = "deploy.runtime",
-      defaultValue = "java11",
+      defaultValue = "java17",
       property = "function.deploy.runtime")
-  String runtime = "java11";
+  String runtime = "java17";
 
   /**
    * The email address of the IAM service account associated with the function at runtime. The
diff --git a/function-maven-plugin/src/test/java/com/google/cloud/functions/plugin/DeployFunctionTest.java b/function-maven-plugin/src/test/java/com/google/cloud/functions/plugin/DeployFunctionTest.java
index 2b441d4e..6f107cff 100644
--- a/function-maven-plugin/src/test/java/com/google/cloud/functions/plugin/DeployFunctionTest.java
+++ b/function-maven-plugin/src/test/java/com/google/cloud/functions/plugin/DeployFunctionTest.java
@@ -53,7 +53,7 @@ public void testDeployFunctionCommandLine() {
             "--env-vars-file=myfile",
             "--set-build-env-vars=env1=a,env2=b",
             "--build-env-vars-file=myfile2",
-            "--runtime=java11",
+            "--runtime=java17",
             "--quiet");
     assertThat(mojo.getCommands()).isEqualTo(expected);
   }
diff --git a/functions-framework-api/pom.xml b/functions-framework-api/pom.xml
index e9994047..6f4ce316 100644
--- a/functions-framework-api/pom.xml
+++ b/functions-framework-api/pom.xml
@@ -77,8 +77,8 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>${maven-compiler-plugin.version}</version>
         <configuration>
-          <source>11</source>
-          <target>11</target>
+          <source>17</source>
+          <target>17</target>
         </configuration>
       </plugin>
       <plugin>
diff --git a/invoker/conformance/pom.xml b/invoker/conformance/pom.xml
index dbb5bbc5..11a51c29 100644
--- a/invoker/conformance/pom.xml
+++ b/invoker/conformance/pom.xml
@@ -20,8 +20,8 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
   </properties>
 
   <dependencies>
diff --git a/invoker/core/pom.xml b/invoker/core/pom.xml
index 05af393a..8108c526 100644
--- a/invoker/core/pom.xml
+++ b/invoker/core/pom.xml
@@ -20,8 +20,8 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <junit.jupiter.version>5.3.2</junit.jupiter.version>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
     <cloudevents.sdk.version>4.0.1</cloudevents.sdk.version>
   </properties>
 
diff --git a/invoker/pom.xml b/invoker/pom.xml
index 40185fcf..c52aba99 100644
--- a/invoker/pom.xml
+++ b/invoker/pom.xml
@@ -56,8 +56,8 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
   </properties>
 
   <dependencyManagement>