diff --git a/appveyor.yml b/appveyor.yml
index a3ad1f17..50206d09 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,15 +20,15 @@ install:
       }
   - ps: |
       Add-Type -AssemblyName System.IO.Compression.FileSystem
-      if (!(Test-Path -Path "C:\groovy\groovy-2.4.8" )) {
+      if (!(Test-Path -Path "C:\groovy\groovy-5.0.0" )) {
         (new-object System.Net.WebClient).DownloadFile(
-          'https://archive.apache.org/dist/groovy/2.4.8/distribution/apache-groovy-binary-2.4.8.zip',
+          'https://archive.apache.org/dist/groovy/5.0.0/distribution/apache-groovy-binary-5.0.0.zip',
           'C:\groovy-bin.zip'
         )
         [System.IO.Compression.ZipFile]::ExtractToDirectory("C:\groovy-bin.zip", "C:\groovy")
       }
   - cmd: SET M2_HOME=C:\maven\apache-maven-3.8.8
-  - cmd: SET GROOVY_HOME=C:\groovy\groovy-2.4.8
+  - cmd: SET GROOVY_HOME=C:\groovy\groovy-5.0.0
   - cmd: SET PATH=%GROOVY_HOME%\bin;%JAVA_HOME%\bin;%M2_HOME%\bin;%PATH%
   - cmd: git config --global core.autocrlf
   - cmd: mvn --version
@@ -37,7 +37,7 @@ install:
 
 cache:
   - C:\maven\apache-maven-3.8.8
-  - C:\groovy\groovy-2.4.8
+  - C:\groovy\groovy-5.0.0
   - C:\Users\appveyor\.m2
 
 matrix:
@@ -102,6 +102,6 @@ build_script:
   - appveyor.cmd
   - ps: echo "Size of caches (bytes):"
   - ps: Get-ChildItem -Recurse 'C:\maven\apache-maven-3.8.8' | Measure-Object -Property Length -Sum
-  - ps: Get-ChildItem -Recurse 'C:\groovy\groovy-2.4.8' | Measure-Object -Property Length -Sum
+  - ps: Get-ChildItem -Recurse 'C:\groovy\groovy-5.0.0' | Measure-Object -Property Length -Sum
   - ps: Get-ChildItem -Recurse 'C:\Users\appveyor\.m2' | Measure-Object -Property Length -Sum
 
diff --git a/checkstyle-tester/diff.groovy b/checkstyle-tester/diff.groovy
index 8ef0f47c..f9b2a3b0 100644
--- a/checkstyle-tester/diff.groovy
+++ b/checkstyle-tester/diff.groovy
@@ -8,6 +8,9 @@ import java.nio.file.Paths
 import java.nio.file.SimpleFileVisitor
 import java.nio.file.attribute.BasicFileAttributes
 import java.util.regex.Pattern
+@GrabConfig(systemClassLoader=true)
+@Grab('info.picocli:picocli:4.2.0')
+import groovy.cli.picocli.CliBuilder
 
 static void main(String[] args) {
     def cliOptions = getCliOptions(args)
diff --git a/devops/docker/no-exception-build-image/jdk-21-groovy-git-mvn-ant-jq/Dockerfile b/devops/docker/no-exception-build-image/jdk-21-groovy-git-mvn-ant-jq/Dockerfile
index eadc46c0..a6c248f2 100644
--- a/devops/docker/no-exception-build-image/jdk-21-groovy-git-mvn-ant-jq/Dockerfile
+++ b/devops/docker/no-exception-build-image/jdk-21-groovy-git-mvn-ant-jq/Dockerfile
@@ -12,7 +12,7 @@ RUN curl -s "https://get.sdkman.io" | bash
 # Install Java 21, Groovy, Maven via SDKMAN
 RUN bash -c "source $SDKMAN_DIR/bin/sdkman-init.sh && \
     sdk install java 21.0.4-tem && \
-    sdk install groovy 3.0.21 && \
+    sdk install groovy 5.0.0 && \
     sdk install maven 3.9.11"
 
 # Update PATH and setup environment
@@ -24,6 +24,4 @@ ENV PATH=$GROOVY_HOME/bin:$SDKMAN_DIR/candidates/maven/current/bin:$JAVA_HOME/bi
 RUN bash -c "source $SDKMAN_DIR/bin/sdkman-init.sh && \
     java -version && \
     groovy --version && \
-    mvn -version && \
-    groovy -e 'new CliBuilder(); println \"CliBuilder OK\"' && \
-    groovy -e 'new AntBuilder(); println \"AntBuilder OK\"'"
+    mvn -version"