diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 00585bc..9433272 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -2,7 +2,7 @@ name: Publish Docker image
 on:
     push:
         tags:
-            - latest
+            - "9"
 
 jobs:
     push_to_registry:
@@ -30,5 +30,5 @@ jobs:
                   # See: https://github.com/docker/buildx/issues/59
                   ACTION: push
                   DOCKER_BUILDKIT: 1
-                  IMAGE_TAG: docker.io/botsudo/phpunit:latest
+                  IMAGE_TAG: docker.io/botsudo/phpunit:9
                   PLATFORM: linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64/v8,linux/ppc64le,linux/s390x
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 96f5d8d..56699b2 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -6,12 +6,13 @@
 # PHPUnit 7	PHP 7.1 - PHP 7.3
 FROM php:8.1-cli-alpine
 
-ARG RELEASE_VERSION=latest
+# https://phar.phpunit.de/
+ARG RELEASE_VERSION=9.6.3
 
 # Metadata params
 ARG VCS_REF
 ARG BUILD_DATE
-ARG DIST_URL="https://phar.phpunit.de/phpunit.phar"
+ARG DIST_URL="https://phar.phpunit.de/phpunit-${RELEASE_VERSION}.phar"
 
 ADD $DIST_URL /usr/bin/phpunit
 RUN chmod +x /usr/bin/phpunit && phpunit --version