diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index 2461754..e44e707 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -42,9 +42,9 @@ jobs:
       # https://github.com/sigstore/cosign-installer
       - name: Install cosign
         if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@main
+        uses: sigstore/cosign-installer@v3.1.1
         with:
-          cosign-release: 'v2.0.0-rc.0'
+          cosign-release: 'v2.1.1'
 
 
       # Workaround: https://github.com/docker/build-push-action/issues/461
diff --git a/Dockerfile b/Dockerfile
index 73a7f39..9c3a029 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM trafex/php-nginx:latest
+FROM trafex/php-nginx:3.1.0
 
 # Add composer
 COPY --from=composer /usr/bin/composer /usr/bin/composer