diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 991fa09..0e4d587 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -23,7 +23,15 @@ jobs:
       - name: lint zammad dockerfile
         uses: brpaz/hadolint-action@master
         with:
-          dockerfile: containers/zammad/Dockerfile
+          dockerfile: containers/zammad-elasticsearch/Dockerfile
+      - name: lint elasticsearch dockerfile
+        uses: brpaz/hadolint-action@master
+        with:
+          dockerfile: containers/zammad-postgresql/Dockerfile
+      - name: lint postgresql dockerfile
+        uses: brpaz/hadolint-action@master
+        with:
+          dockerfile: containers/zammad/Dockerfile                    
 
   install-docker-compose:
     timeout-minutes: 30
diff --git a/containers/zammad-elasticsearch/Dockerfile b/containers/zammad-elasticsearch/Dockerfile
index 3321a17..04c578d 100644
--- a/containers/zammad-elasticsearch/Dockerfile
+++ b/containers/zammad-elasticsearch/Dockerfile
@@ -1,5 +1,4 @@
 FROM docker.elastic.co/elasticsearch/elasticsearch:7.6.0
-MAINTAINER Zammad <info@zammad.org>
 ARG BUILD_DATE
 
 LABEL org.label-schema.build-date="$BUILD_DATE" \
diff --git a/containers/zammad-postgresql/Dockerfile b/containers/zammad-postgresql/Dockerfile
index d40260b..b5ae3be 100644
--- a/containers/zammad-postgresql/Dockerfile
+++ b/containers/zammad-postgresql/Dockerfile
@@ -1,6 +1,5 @@
 FROM postgres:9.6.17-alpine
 
-MAINTAINER Zammad <info@zammad.org>
 ARG BUILD_DATE
 
 LABEL org.label-schema.build-date="$BUILD_DATE" \
diff --git a/containers/zammad/Dockerfile b/containers/zammad/Dockerfile
index 0403b77..9c4c371 100644
--- a/containers/zammad/Dockerfile
+++ b/containers/zammad/Dockerfile
@@ -2,7 +2,6 @@ FROM ruby:2.5.5-slim AS builder
 # note: zammad is currently incompatible to alpine because of: 
 # https://github.com/docker-library/ruby/issues/113
 
-MAINTAINER Zammad <info@zammad.org>
 ARG BUILD_DATE
 ARG DEBIAN_FRONTEND=noninteractive