diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index b8259cf..79b6849 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -11,11 +11,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up JDK 8
-      uses: actions/setup-java@v2
+    - uses: actions/checkout@v4
+    - name: Set up JDK 21
+      uses: actions/setup-java@v4
       with:
-        java-version: '8'
+        java-version: '21'
         distribution: 'adopt'
     - name: Grant execute permission for gradlew
       run: chmod +x gradlew
diff --git a/build.gradle b/build.gradle
index de6cf0c..996e99d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -16,9 +16,11 @@ sourceSets {
     }
 }
 
-sourceCompatibility = 1.8
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+}
 
-project.buildDir = 'target'
+project.layout.buildDirectory = 'target'
 
 repositories {
     mavenCentral()
@@ -31,31 +33,32 @@ dependencies {
 
     // mandatory dependencies for using Spock
     // note: please use same Groovy version as on Jenkins
-    implementation "org.codehaus.groovy:groovy-all:2.4.12"
+    implementation "org.codehaus.groovy:groovy-all:2.4.21"
     implementation "com.cloudbees:groovy-cps:1.31@jar", withoutIcu
-    implementation "org.jenkins-ci.main:jenkins-core:2.225", withoutIcu
-    implementation "org.jenkins-ci.plugins:badge:1.8@jar"
+    implementation "org.jenkins-ci.main:jenkins-core:2.452", withoutIcu
+    implementation "org.jenkins-ci.plugins:badge:1.13@jar"
     implementation "org.jenkins-ci.plugins:pipeline-maven:3.9.3@jar" // dependency for MavenReport
     implementation "org.jenkins-ci.plugins:credentials-binding:1.27.1@jar"
 
-    implementation "org.slf4j:jcl-over-slf4j:1.7.25"
-    testImplementation "org.slf4j:log4j-over-slf4j:1.7.25"
-    testImplementation "org.slf4j:slf4j-api:1.7.25"
+    implementation "org.slf4j:jcl-over-slf4j:2.0.13"
+    testImplementation "org.slf4j:log4j-over-slf4j:2.0.13"
+    testImplementation "org.slf4j:slf4j-api:2.0.12"
 
-    testImplementation "ch.qos.logback:logback-core:1.2.3"
-    testImplementation "ch.qos.logback:logback-classic:1.2.3"
-    testImplementation "com.google.guava:guava:20.0"
+    testImplementation "ch.qos.logback:logback-core:1.5.6"
+    testImplementation "ch.qos.logback:logback-classic:1.5.6"
+    testImplementation "com.google.guava:guava:33.2.1-jre"
 
-    testImplementation "org.spockframework:spock-core:1.3-groovy-2.4@jar"
+    testImplementation "org.codehaus.groovy:groovy-all:3.0.21"
+    testImplementation "org.spockframework:spock-core:2.3-groovy-3.0@jar"
 
     // Jenkins Pipeline Unit + JUnit 4
     testImplementation "com.lesfurets:jenkins-pipeline-unit:1.13"
-    testImplementation "org.assertj:assertj-core:3.22.0"
+    testImplementation "org.assertj:assertj-core:3.26.0"
 
     // Jenkins related
-    testImplementation "com.homeaway.devtools.jenkins:jenkins-spock:2.1.4"
-    testImplementation "javax.servlet:javax.servlet-api:3.1.0"
-    testImplementation "org.jenkins-ci.main:jenkins-core:2.225", withoutIcu
+    testImplementation "com.homeaway.devtools.jenkins:jenkins-spock:2.1.5"
+    testImplementation "javax.servlet:javax.servlet-api:4.0.1"
+    testImplementation "org.jenkins-ci.main:jenkins-core:2.452", withoutIcu
     testImplementation "org.jenkins-ci.plugins.workflow:workflow-api:2.40@jar"
     testImplementation "org.jenkins-ci.plugins.workflow:workflow-step-api:2.22@jar"
     testImplementation "org.jenkins-ci.plugins.workflow:workflow-cps:2.78@jar"
@@ -72,9 +75,9 @@ dependencies {
 
 // this is needed for spock to find all the source code in the var directory
 task copyGlobalLibVars (type: Copy) {
-    from "$rootDir/vars"
+    from layout.projectDirectory.dir("vars")
     include '**/*.groovy'
-    into "$buildDir/classes/vars"
+    into layout.buildDirectory.dir("classes/vars")
 }
 
 compileTestGroovy {
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 6c9a224..0d18421 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/jenkins/docker-compose.yaml b/jenkins/docker-compose.yaml
index 06d37b2..015d008 100644
--- a/jenkins/docker-compose.yaml
+++ b/jenkins/docker-compose.yaml
@@ -5,8 +5,8 @@ services:
     privileged: true
     user: root
     ports:
-      - 8081:8080
-      - 50000:50000
+      - "8081:8080"
+      - "50000:50000"
     container_name: jenkins
     volumes:
       - ~/jenkins:/var/jenkins_home
diff --git a/test/groovy/util/Result.groovy b/test/groovy/util/Result.groovy
index c7db8d9..382c294 100644
--- a/test/groovy/util/Result.groovy
+++ b/test/groovy/util/Result.groovy
@@ -7,7 +7,7 @@ class Result {
 
     def Result() {}
 
-    def int status() {
+    int status() {
         return status
     }
 }
\ No newline at end of file
diff --git a/test/groovy/vars/KustomizeTest.groovy b/test/groovy/vars/KustomizeTest.groovy
index f6f68d1..c3f184d 100644
--- a/test/groovy/vars/KustomizeTest.groovy
+++ b/test/groovy/vars/KustomizeTest.groovy
@@ -1,7 +1,7 @@
 package groovy.vars
 
 import static com.lesfurets.jenkins.unit.MethodCall.callArgsToString
-import static org.assertj.core.api.Assertions.*;
+import static org.assertj.core.api.Assertions.*
 
 import com.lesfurets.jenkins.unit.BasePipelineTest
 import org.junit.Before
@@ -9,7 +9,7 @@ import org.junit.Test
 
 class KustomizeTest extends BasePipelineTest {
 
-    Script kustomize;
+    Script kustomize
 
     @Before
     @Override
diff --git a/vars/cleanBuilds.groovy b/vars/cleanBuilds.groovy
index e91e4a4..640c812 100644
--- a/vars/cleanBuilds.groovy
+++ b/vars/cleanBuilds.groovy
@@ -5,7 +5,7 @@ import com.jenkinsci.plugins.badge.action.BadgeAction
 // the function implements how many build per environment should be kept
 // parameter is maxKeepBuilds
 def call(Map args) {
-  def maxNumberToKeepBuilds = args?.maxKeepBuilds ?: 10;
+  def maxNumberToKeepBuilds = args?.maxKeepBuilds ?: 10
 
   def environmentBuildCount = [:]
   Jenkins.instance.getItemByFullName(args.job)
diff --git a/vars/openshiftUtils.groovy b/vars/openshiftUtils.groovy
index fae1d81..c231080 100644
--- a/vars/openshiftUtils.groovy
+++ b/vars/openshiftUtils.groovy
@@ -10,7 +10,7 @@
 // credentialsId -> credentials for the OpenShift login
 // namespace -> true adds NAMESPACE_NAME param
 //
-def void applyTemplate(String ocpUrl, String ocpProject, String templateFile, String credentialsId, boolean namespace) {
+void applyTemplate(String ocpUrl, String ocpProject, String templateFile, String credentialsId, boolean namespace) {
 
     echo "-- start resource update by template --"
     echo "OpenShift server URL: $ocpUrl"
@@ -47,7 +47,7 @@ def void applyTemplate(String ocpUrl, String ocpProject, String templateFile, St
 // envFile -> environment file
 // namespace -> true adds NAMESPACE_NAME param
 //
-def void applyTemplateWithEnvFile(String ocpUrl, String ocpProject, String templateFile, String credentialsId, String envFile, boolean namespace) {
+void applyTemplateWithEnvFile(String ocpUrl, String ocpProject, String templateFile, String credentialsId, String envFile, boolean namespace) {
 
     echo "-- start resource update by template with environment file --"
     echo "OpenShift server URL: $ocpUrl"