diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2c93f8a1fab6ddd392cf8ff03049744e24528288..1ed8591d570261e9578cbd56cb4b7619c9e245c2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,7 +6,7 @@ stages:
 
 test:
   stage: test
-  image: openjdk:17-jdk-slim
+  image: openjdk:21-jdk-slim
   tags:
     - docker
   script:
@@ -15,7 +15,7 @@ test:
 
 sonar:
   stage: sonar
-  image: openjdk:17-jdk-slim
+  image: openjdk:21-jdk-slim
   only:
     - develop
     - /^release/
@@ -66,7 +66,7 @@ build_and_push_release_image:
 
 mend:
   stage: mend
-  image: openjdk:17-jdk-slim
+  image: openjdk:21-jdk-slim
   only:
     - /^release/
   variables:
diff --git a/docs/DEVELOPMENT.md b/docs/DEVELOPMENT.md
index 8e2c6c24881471b2d9466540a890323ce49fb109..9414c7c31d3cf96e0b191d99204512eb33ba73a3 100644
--- a/docs/DEVELOPMENT.md
+++ b/docs/DEVELOPMENT.md
@@ -2,7 +2,7 @@
 
 ### Technologies
 
-* Java 17
+* Java 21
 * Spring Boot
 * freemarker
 * Gitlab4j
@@ -12,7 +12,7 @@
 ### Running nmaas Platform on local machine
 
 #### Prerequisites
-Install Java 17 jdk
+Install Java 21 jdk
 
 #### Running the software
 In order to build and run the nmaas Platform software locally execute *./gradlew bootRun* in project root directory.