diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d9990ac3..a0394415 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,10 +32,10 @@ jobs:
       working-directory: com.microsoft.copilot.eclipse.core/copilot-agent
       run: npm i -f
 
-    - name: Set up JDK 17
+    - name: Set up JDK 21
       uses: actions/setup-java@b843ebf9b913146b38da2eaa7aeddf76074ae1ad # v6.1.0
       with:
-        java-version: '17'
+        java-version: '21'
         distribution: 'temurin'
         cache: maven
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e78e21d4..ff5f3087 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -16,8 +16,8 @@ When you submit a pull request, a CLA bot will automatically determine whether y
 
 ### Prerequisites
 
-- **Java 17** or later (CI uses Temurin 17; use a newer JDK if required by your Eclipse IDE)
-- **Maven 3.8+** (or use the provided Maven wrapper `./mvnw`)
+- **Java 21** or later to run the build (CI uses Temurin 21; bundles still target Java 17)
+- **Maven 3.9.9+** (or use the provided Maven wrapper `./mvnw`)
 - **Node.js 22.13** or later, with npm
 - **Eclipse IDE for Eclipse Committers 2024-03** or later (for development)
 - Recommended: **Eclipse Checkstyle plugin** for code style compliance
diff --git a/pom.xml b/pom.xml
index ba917990..067fbb08 100644
--- a/pom.xml
+++ b/pom.xml
@@ -13,7 +13,7 @@
 	<properties>
 		<copilot-plugin-version>0.21.0-SNAPSHOT</copilot-plugin-version>
 		<base.name>GitHub Copilot</base.name>
-		<tycho-version>4.0.13</tycho-version>
+		<tycho-version>5.0.4</tycho-version>
 		<checkstyle-version>3.6.0</checkstyle-version>
 		<!-- Kill a forked test JVM that stops making progress instead of letting it stall the build
 		     indefinitely; tycho-surefire reads this as forkedProcessTimeoutInSeconds. -->