diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index eb9c706ab4eb5aebe4624e655a331d17aba39129..a75c209c51b246c04a90db1d9cbe5efe79a1505b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-image: eclipse-temurin:8
+image: eclipse-temurin:11
 
 variables:
   GRADLE_ARGS: --no-daemon --stacktrace --warning-mode=all
diff --git a/tlatools/org.lamport.tlatools/build.gradle b/tlatools/org.lamport.tlatools/build.gradle
index f39656b73ada45955ab54aa6d6dc0c1daa5560bf..ef93cc2d6005e29ba01232307108f34ecad38fe8 100644
--- a/tlatools/org.lamport.tlatools/build.gradle
+++ b/tlatools/org.lamport.tlatools/build.gradle
@@ -6,8 +6,8 @@ project.version = '1.0.3-SNAPSHOT'
 project.group = 'de.hhu.stups'
 project.archivesBaseName = 'tlatools'
 
-project.sourceCompatibility = JavaVersion.VERSION_1_8
-project.targetCompatibility = JavaVersion.VERSION_1_8
+project.sourceCompatibility = JavaVersion.VERSION_11
+project.targetCompatibility = JavaVersion.VERSION_11
 
 repositories {
 	mavenCentral()