diff --git a/.env b/.env
index 5d7c3f1..56f17e2 100644
--- a/.env
+++ b/.env
@@ -1,5 +1,5 @@
 # don't forget to add the minus before the version
-# example: VERSION=-2.1.0-13
+# example: VERSION=-2.9.0-1
 IMAGE_REPO=zammad/zammad-docker-compose
 VERSION=
-RESTART=always
\ No newline at end of file
+RESTART=always
diff --git a/Dockerfile b/Dockerfile
index d17aad0..822e3e0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,5 +9,5 @@ LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.vcs-url="https://github.com/zammad/zammad" \
       org.label-schema.vcs-type="Git" \
       org.label-schema.vendor="Zammad" \
-      org.label-schema.schema-version="1.2" \
+      org.label-schema.schema-version="2.9.0" \
       org.label-schema.docker.cmd="sysctl -w vm.max_map_count=262144;docker-compose up"
diff --git a/containers/zammad-elasticsearch/Dockerfile b/containers/zammad-elasticsearch/Dockerfile
index 40f442f..cc89306 100644
--- a/containers/zammad-elasticsearch/Dockerfile
+++ b/containers/zammad-elasticsearch/Dockerfile
@@ -10,7 +10,7 @@ LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.vcs-url="https://github.com/zammad/zammad" \
       org.label-schema.vcs-type="Git" \
       org.label-schema.vendor="Zammad" \
-      org.label-schema.schema-version="1.2" \
+      org.label-schema.schema-version="2.9.0" \
       org.label-schema.docker.cmd="sysctl -w vm.max_map_count=262144;docker-compose up"
 
 RUN /usr/share/elasticsearch/bin/elasticsearch-plugin remove x-pack --purge && \
diff --git a/containers/zammad-memcached/Dockerfile b/containers/zammad-memcached/Dockerfile
index bc1ecd4..82bb04b 100644
--- a/containers/zammad-memcached/Dockerfile
+++ b/containers/zammad-memcached/Dockerfile
@@ -11,7 +11,7 @@ LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.vcs-url="https://github.com/zammad/zammad" \
       org.label-schema.vcs-type="Git" \
       org.label-schema.vendor="Zammad" \
-      org.label-schema.schema-version="1.2" \
+      org.label-schema.schema-version="2.9.0" \
       org.label-schema.docker.cmd="sysctl -w vm.max_map_count=262144;docker-compose up"
 
 # docker init
diff --git a/containers/zammad-postgresql/Dockerfile b/containers/zammad-postgresql/Dockerfile
index 6a364c0..aa47db6 100644
--- a/containers/zammad-postgresql/Dockerfile
+++ b/containers/zammad-postgresql/Dockerfile
@@ -15,7 +15,7 @@ LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.vcs-url="https://github.com/zammad/zammad" \
       org.label-schema.vcs-type="Git" \
       org.label-schema.vendor="Zammad" \
-      org.label-schema.schema-version="1.2" \
+      org.label-schema.schema-version="2.9.0" \
       org.label-schema.docker.cmd="sysctl -w vm.max_map_count=262144;docker-compose up"
 
 # copy backup script
diff --git a/containers/zammad/Dockerfile b/containers/zammad/Dockerfile
index ffb05f1..a123e03 100644
--- a/containers/zammad/Dockerfile
+++ b/containers/zammad/Dockerfile
@@ -1,18 +1,33 @@
-FROM ruby:2.4.4-slim
+FROM ruby:2.4.4-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
 
-ENV ZAMMAD_DIR /opt/zammad
-ENV ZAMMAD_USER zammad
-ENV RAILS_ENV production
-ENV RAILS_SERVER puma
-ENV PROJECT_URL https://github.com/zammad/zammad
-ENV GIT_URL ${PROJECT_URL}.git
 ENV GIT_BRANCH stable
-ENV ZAMMAD_TMP_DIR /tmp/zammad-${GIT_BRANCH}
-ENV TAR_GZ_URL ${PROJECT_URL}/archive/${GIT_BRANCH}.tar.gz
+ENV GIT_URL ${PROJECT_URL}.git
 ENV GOSU_VERSION 1.11
+ENV PROJECT_URL https://github.com/zammad/zammad
+ENV RAILS_ENV production
+ENV TAR_GZ_URL ${PROJECT_URL}/archive/${GIT_BRANCH}.tar.gz
+ENV ZAMMAD_DIR /opt/zammad
 ENV ZAMMAD_READY_FILE ${ZAMMAD_DIR}/tmp/zammad.ready
+ENV ZAMMAD_TMP_DIR /tmp/zammad-${GIT_BRANCH}
+ENV ZAMMAD_USER zammad
+
+# install zammad
+COPY containers/zammad/setup.sh /tmp
+RUN chmod +x /tmp/setup.sh; \
+    /tmp/setup.sh install
+
+
+FROM ruby:2.4.4-slim
+
+MAINTAINER Zammad <info@zammad.org>
+ARG BUILD_DATE
+ARG DEBIAN_FRONTEND=noninteractive
 
 LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.name="Zammad" \
@@ -22,33 +37,23 @@ LABEL org.label-schema.build-date="$BUILD_DATE" \
       org.label-schema.vcs-url="https://github.com/zammad/zammad" \
       org.label-schema.vcs-type="Git" \
       org.label-schema.vendor="Zammad" \
-      org.label-schema.schema-version="1.2" \
+      org.label-schema.schema-version="2.9.0" \
       org.label-schema.docker.cmd="sysctl -w vm.max_map_count=262144;docker-compose up"
 
-# install dependencies & gosu
-RUN BUILD_DEPENDENCIES="build-essential ca-certificates curl dirmngr git gnupg2 libffi-dev libpq5 libpq-dev nginx rsync" && \
-  set -ex && \
-  apt-get update && apt-get install -y --no-install-recommends ${BUILD_DEPENDENCIES} && rm -rf /var/lib/apt/lists/* && \
-  curl -s -J -L -o /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/${GOSU_VERSION}/gosu-$(dpkg --print-architecture)" && \
-  chmod +x /usr/local/bin/gosu && \
-  gosu nobody true
+ENV GIT_BRANCH stable
+ENV RAILS_ENV production
+ENV ZAMMAD_DIR /opt/zammad
+ENV ZAMMAD_READY_FILE ${ZAMMAD_DIR}/tmp/zammad.ready
+ENV ZAMMAD_TMP_DIR /tmp/zammad-${GIT_BRANCH}
+ENV ZAMMAD_USER zammad
 
-# install zammad
-RUN groupadd -g 1000 ${ZAMMAD_USER} && \
-  useradd -M -d ${ZAMMAD_DIR} -s /bin/bash -u 1000 -g 1000 ${ZAMMAD_USER} && \
-  cd $(dirname ${ZAMMAD_TMP_DIR}) && \
-  curl -s -J -L -O "${TAR_GZ_URL}" && \
-  tar -xzf zammad-${GIT_BRANCH}.tar.gz && \
-  rm zammad-${GIT_BRANCH}.tar.gz && \
-  cd ${ZAMMAD_TMP_DIR} && \
-  bundle install --without test development mysql && \
-  contrib/packager.io/fetch_locales.rb && \
-  sed -e 's#.*adapter: postgresql#  adapter: nulldb#g' -e 's#.*username:.*#  username: postgres#g' -e 's#.*password:.*#  password: \n  host: zammad-postgresql\n#g' < contrib/packager.io/database.yml.pkgr > config/database.yml && \
-  sed -i '/# Use a different logger for distributed setups./a \ \ config.logger = Logger.new(STDOUT)' config/environments/production.rb && \
-  sed -i 's/.*scheduler_\(err\|out\).log.*//g' script/scheduler.rb && \
-  bundle exec rake assets:precompile && \
-  rm -r tmp/cache && \
-  chown -R ${ZAMMAD_USER}:${ZAMMAD_USER} ${ZAMMAD_TMP_DIR}
+COPY containers/zammad/setup.sh /tmp
+RUN chmod +x /tmp/setup.sh; \
+    /tmp/setup.sh run
+
+COPY --from=builder ${ZAMMAD_TMP_DIR} ${ZAMMAD_TMP_DIR}
+COPY --from=builder /usr/local/bin/gosu /usr/local/bin/gosu
+COPY --from=builder /usr/local/bundle /usr/local/bundle
 
 # docker init
 COPY containers/zammad/docker-entrypoint.sh /
diff --git a/containers/zammad/docker-entrypoint.sh b/containers/zammad/docker-entrypoint.sh
old mode 100644
new mode 100755
index 63802ce..3d66b13
--- a/containers/zammad/docker-entrypoint.sh
+++ b/containers/zammad/docker-entrypoint.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 
@@ -129,10 +129,12 @@ if [ "$1" = 'zammad-railsserver' ]; then
 
   echo "starting railsserver..."
 
+  #shellcheck disable=SC2101
   exec gosu "${ZAMMAD_USER}":"${ZAMMAD_USER}" bundle exec rails server puma -b [::] -p "${ZAMMAD_RAILSSERVER_PORT}" -e "${RAILS_ENV}"
 fi
 
 
+
 # zammad-scheduler
 if [ "$1" = 'zammad-scheduler' ]; then
   check_zammad_ready
diff --git a/containers/zammad/setup.sh b/containers/zammad/setup.sh
new file mode 100644
index 0000000..cb94feb
--- /dev/null
+++ b/containers/zammad/setup.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env sh
+set -e
+
+# install dependencies
+if [ "$1" = 'install' ]; then
+  PACKAGES="build-essential curl git libimlib2-dev libpq-dev"
+elif [ "$1" = 'run' ]; then
+  PACKAGES="curl libimlib2 libimlib2-dev libpq5 nginx rsync"
+fi
+
+apt-get update
+apt-get upgrade -y
+apt-get install -y --no-install-recommends ${PACKAGES}
+rm -rf /var/lib/apt/lists/*
+
+# install gosu
+if [ "$1" = 'install' ]; then
+  curl -s -J -L -o /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/${GOSU_VERSION}/gosu-$(dpkg --print-architecture)"
+  chmod +x /usr/local/bin/gosu
+  gosu nobody true
+fi
+
+# install zammad
+groupadd -g 1000 "${ZAMMAD_USER}"
+useradd -M -d "${ZAMMAD_DIR}" -s /bin/bash -u 1000 -g 1000 "${ZAMMAD_USER}"
+
+if [ "$1" = 'install' ]; then
+  cd "$(dirname "${ZAMMAD_TMP_DIR}")"
+  curl -s -J -L -O "${TAR_GZ_URL}"
+  tar -xzf zammad-"${GIT_BRANCH}".tar.gz
+  rm zammad-"${GIT_BRANCH}".tar.gz
+  cd "${ZAMMAD_TMP_DIR}"
+  bundle install --without test development mysql
+  contrib/packager.io/fetch_locales.rb
+  sed -e 's#.*adapter: postgresql#  adapter: nulldb#g' -e 's#.*username:.*#  username: postgres#g' -e 's#.*password:.*#  password: \n  host: zammad-postgresql\n#g' < contrib/packager.io/database.yml.pkgr > config/database.yml
+  sed -i '/# Use a different logger for distributed setups./a \ \ config.logger = Logger.new(STDOUT)' config/environments/production.rb
+  sed -i 's/.*scheduler_\(err\|out\).log.*//g' script/scheduler.rb
+  bundle exec rake assets:precompile
+  rm -r tmp/cache
+  chown -R "${ZAMMAD_USER}":"${ZAMMAD_USER}" "${ZAMMAD_TMP_DIR}"
+fi