diff --git a/CHANGELOG.md b/CHANGELOG.md
index 528840d..c00a088 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project follows Zammad versioning.
 
+## [3.0.0] - 2019-06-10
+### Changed
+  - Upgrade Zammad version to 3.0.0
+
+### Fixed
+  - Shellcheck all scripts
+
 ## [2.9.0] - 2019-02-20
 ### Changed
   - Upgrade Zammad version to 2.9.0
diff --git a/Makefile b/Makefile
index 9fe16f5..c5911c8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 NAME = osixia/zammad
-VERSION = 2.9.0
+VERSION = 3.0.0
 
 .PHONY: build build-nocache test tag-latest push push-latest release git-tag-version
 
diff --git a/README.md b/README.md
index dfdd880..c1796a8 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 ![Docker Stars](https://img.shields.io/docker/stars/osixia/zammad.svg)
 ![](https://images.microbadger.com/badges/image/osixia/zammad.svg)
 
-Latest release: 2.9.0 - Zammad 2.9.0 - [Changelog](CHANGELOG.md) | [Docker Hub](https://hub.docker.com/r/osixia/zammad/) 
+Latest release: 3.0.0 - Zammad 3.0.0 - [Changelog](CHANGELOG.md) | [Docker Hub](https://hub.docker.com/r/osixia/zammad/) 
 
 **A docker image to run Zammad.**
 
diff --git a/example/docker-compose.yml b/example/docker-compose.yml
index 645c8c9..e5da8b1 100644
--- a/example/docker-compose.yml
+++ b/example/docker-compose.yml
@@ -32,7 +32,7 @@ services:
       - mariadb:/var/lib/mysql
 
   zammad:
-    image: osixia/zammad:2.9.0
+    image: osixia/zammad:3.0.0
     command: -l info
     labels:
       - "io.rancher.container.pull_image: always"
diff --git a/example/kubernetes/zammad-deployment.yaml b/example/kubernetes/zammad-deployment.yaml
index 640b34c..490f21f 100644
--- a/example/kubernetes/zammad-deployment.yaml
+++ b/example/kubernetes/zammad-deployment.yaml
@@ -15,7 +15,7 @@ spec:
       automountServiceAccountToken: false
       containers:
         - name: zammad
-          image: osixia/zammad:2.9.0
+          image: osixia/zammad:3.0.0
           imagePullPolicy: Always
           resources:
             requests:
diff --git a/image/Dockerfile b/image/Dockerfile
index 68cbbd8..1ee1f10 100644
--- a/image/Dockerfile
+++ b/image/Dockerfile
@@ -4,8 +4,8 @@ ENV ZAMMAD_DIR /home/zammad
 ENV ZAMMAD_USER zammad
 ENV RAILS_ENV production
 
-ARG ZAMMAD_VERSION=2.9.0
-ARG ZAMMAD_MD5=08bd2f55770f23ee780a7dbd5c8c4cc8
+ARG ZAMMAD_VERSION=3.0.0
+ARG ZAMMAD_MD5=5170cfc115ee90e853c1180578fc30da
 
 ARG GOSU_VERSION=1.10
 
diff --git a/image/service/backup/assets/tool/zammad-backup b/image/service/backup/assets/tool/zammad-backup
index eb2fbfd..db4e3b4 100755
--- a/image/service/backup/assets/tool/zammad-backup
+++ b/image/service/backup/assets/tool/zammad-backup
@@ -6,29 +6,27 @@ backupFileSuffix="-zammad.tar.gz"
 backupDbSuffix="-zammad-db.tar.gz"
 databaseFile="database.sql"
 
-source /container/run/environment.sh
+. /container/run/environment.sh
 
 # delete backups that are over $ZAMMAD_BACKUP_TTL days
-find $backupPath -type f -mtime +$ZAMMAD_BACKUP_TTL -exec rm {} \;
+find "${backupPath}" -type f -mtime +"${ZAMMAD_BACKUP_TTL}" -exec rm {} \;
 
 # date format for the dump file name
 dateFileFormat="+%Y%m%dT%H%M%S"
-backupFilePath="$backupPath/$(date "$dateFileFormat")$backupFileSuffix"
+backupFilePath="${backupPath}/$(date "${dateFileFormat}")${backupFileSuffix}"
 
 # save config and plugins except default ones
-tar -czf $backupFilePath -C / ${ZAMMAD_DIR:1}
-chmod 600 $backupFilePath
+tar -czf "${backupFilePath}" -C / "${ZAMMAD_DIR:1}"
+chmod 600 "${backupFilePath}"
 
 # backup database
 . /container/service/backup/assets/tool/zammad-get-db-params
-rm -rf $databaseFile || true
+rm -rf "${databaseFile}" || true
 
-mysqldump -u $databaseUser -p$databasePassword --host $host $database > $databaseFile
+mysqldump -u "${databaseUser}" -p"${databasePassword}" --host "${host}" "${database}" > "${databaseFile}"
 
-backupFilePath="$backupPath/$(date "$dateFileFormat")$backupDbSuffix"
-tar -czf $backupFilePath $databaseFile
-chmod 600 $backupFilePath
+backupFilePath="${backupPath}/$(date "${dateFileFormat}")${backupDbSuffix}"
+tar -czf "${backupFilePath}" "${databaseFile}"
+chmod 600 "${backupFilePath}"
 
-rm -rf $databaseFile
-
-exit 0
+rm -rf "${databaseFile}"
diff --git a/image/service/backup/assets/tool/zammad-get-db-params b/image/service/backup/assets/tool/zammad-get-db-params
index e6657c7..66f052a 100755
--- a/image/service/backup/assets/tool/zammad-get-db-params
+++ b/image/service/backup/assets/tool/zammad-get-db-params
@@ -3,7 +3,7 @@
 # get database name, user and password from configuration
 # /!\ configuration must use simple quote :)
 # and it's a bad idea to have ' in your username, password and database name
-host="$(grep 'host:' < ${ZAMMAD_DIR}/config/database.yml | sed -e 's/.*host:\(\| \)//g')"
-databaseUser="$(grep 'username:' < ${ZAMMAD_DIR}/config/database.yml | sed -e 's/.*username:\(\| \)//g')"
-databasePassword="$(grep 'password:' < ${ZAMMAD_DIR}/config/database.yml | sed -e 's/.*password:\(\| \)//g')"
-database="$(grep 'database:' < ${ZAMMAD_DIR}/config/database.yml | sed -e 's/.*database:\(\| \) //g')"
+host="$(grep 'host:' < "${ZAMMAD_DIR}/config/database.yml" | sed -e 's/.*host:\(\| \)//g')"
+databaseUser="$(grep 'username:' < "${ZAMMAD_DIR}/config/database.yml" | sed -e 's/.*username:\(\| \)//g')"
+databasePassword="$(grep 'password:' < "${ZAMMAD_DIR}/config/database.yml" | sed -e 's/.*password:\(\| \)//g')"
+database="$(grep 'database:' < "${ZAMMAD_DIR}/config/database.yml" | sed -e 's/.*database:\(\| \) //g')"
diff --git a/image/service/backup/assets/tool/zammad-restore b/image/service/backup/assets/tool/zammad-restore
index 7389086..25086e5 100755
--- a/image/service/backup/assets/tool/zammad-restore
+++ b/image/service/backup/assets/tool/zammad-restore
@@ -8,26 +8,26 @@ databaseFile="database.sql"
 
 for file in "$@"
 do
-    echo "Processing file $file"
-
-    if $(echo "$file" | grep -q -e "$backupFileSuffix"); then
+    echo "Processing file ${file}"
+    
+    if echo "${file}" | grep -q -e "$backupFileSuffix"; then
         echo "Restore zammad files"
-        tar -xvzf $backupPath/$file -C /
-        echo "done :)"
-    elif $(echo "$file" | grep -q -e "$backupDbSuffix"); then
+        tar -xvzf "${backupPath}/${file}" -C /
+        echo "done :)"    
+    elif echo "${file}" | grep -q -e "${backupDbSuffix}"; then
         echo "Restore zammad database"
         . /container/service/backup/assets/tool/zammad-get-db-params
-
-        rm -rf $databaseFile || true
-        tar -xvzf $backupPath/$file
-
-        mysql -u $databaseUser -p$databasePassword --host $host $database < $databaseFile
-
-        rm -rf $databaseFile
-
+        
+        rm -rf "${databaseFile}" || true
+        tar -xvzf "${backupPath}/${file}"
+        
+        mysql -u "${databaseUser}" -p"${databasePassword}" --host "${host}" "${database}" < "${databaseFile}"
+        
+        rm -rf "${databaseFile}"
+        
         echo "done :)"
     else
-      echo "Error: Unknown file type"
+        echo "Error: Unknown file type"
     fi
 done
 
diff --git a/image/service/backup/startup.sh b/image/service/backup/startup.sh
index 038968d..060933f 100755
--- a/image/service/backup/startup.sh
+++ b/image/service/backup/startup.sh
@@ -5,20 +5,18 @@
 log-helper level eq trace && set -x
 
 # install image tools
-ln -sf ${CONTAINER_SERVICE_DIR}/backup/assets/tool/* /sbin/
+ln -sf "${CONTAINER_SERVICE_DIR}"/backup/assets/tool/* /sbin/
 
 # add cron jobs
-ln -sf ${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs /etc/cron.d/backup
-chmod 600 ${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs
+ln -sf "${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs" /etc/cron.d/backup
+chmod 600 "${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs"
 
 FIRST_START_DONE="${CONTAINER_STATE_DIR}/docker-backup-backup-first-start-done"
 # container first start
-if [ ! -e "$FIRST_START_DONE" ]; then
-
-  # adapt cronjobs file
-  sed -i "s|{{ ZAMMAD_BACKUP_CRON_EXP }}|${ZAMMAD_BACKUP_CRON_EXP}|g" ${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs
-
-  touch $FIRST_START_DONE
+if [ ! -e "${FIRST_START_DONE}" ]; then
+    
+    # adapt cronjobs file
+    sed -i "s|{{ ZAMMAD_BACKUP_CRON_EXP }}|${ZAMMAD_BACKUP_CRON_EXP}|g" "${CONTAINER_SERVICE_DIR}/backup/assets/cronjobs"
+    
+    touch "${FIRST_START_DONE}"
 fi
-
-exit 0
diff --git a/image/service/nginx/startup.sh b/image/service/nginx/startup.sh
index 613b5eb..791cba6 100755
--- a/image/service/nginx/startup.sh
+++ b/image/service/nginx/startup.sh
@@ -6,19 +6,17 @@ log-helper level eq trace && set -x
 
 FIRST_START_DONE="${CONTAINER_STATE_DIR}/docker-help-center-nginx-first-start-done"
 # container first start
-if [ ! -e "$FIRST_START_DONE" ]; then
+if [ ! -e "${FIRST_START_DONE}" ]; then
 
   # generate a certificate and key if files don't exists
   # https://github.com/osixia/docker-light-baseimage/blob/stable/image/service-available/:ssl-tools/assets/tool/ssl-helper
-  ssl-helper ${SSL_HELPER_PREFIX} "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/$ZAMMAD_SSL_CRT_FILENAME" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/$ZAMMAD_SSL_KEY_FILENAME" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/$ZAMMAD_SSL_CA_CRT_FILENAME"
-  cat ${CONTAINER_SERVICE_DIR}/nginx/assets/certs/$ZAMMAD_SSL_CRT_FILENAME ${CONTAINER_SERVICE_DIR}/nginx/assets/certs/$ZAMMAD_SSL_CA_CRT_FILENAME > /nginx-combined-cert.crt
+  ssl-helper "${SSL_HELPER_PREFIX}" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/${ZAMMAD_SSL_CRT_FILENAME}" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/${ZAMMAD_SSL_KEY_FILENAME}" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/${ZAMMAD_SSL_CA_CRT_FILENAME}"
+  cat "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/${ZAMMAD_SSL_CRT_FILENAME}" "${CONTAINER_SERVICE_DIR}/nginx/assets/certs/${ZAMMAD_SSL_CA_CRT_FILENAME}" > /nginx-combined-cert.crt
 
-  sed -i "s|{{ CONTAINER_SERVICE_DIR }}|${CONTAINER_SERVICE_DIR}|g" ${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf
-  sed -i "s|{{ ZAMMAD_SSL_KEY_FILENAME }}|${ZAMMAD_SSL_KEY_FILENAME}|g" ${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf
+  sed -i "s|{{ CONTAINER_SERVICE_DIR }}|${CONTAINER_SERVICE_DIR}|g" "${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf"
+  sed -i "s|{{ ZAMMAD_SSL_KEY_FILENAME }}|${ZAMMAD_SSL_KEY_FILENAME}|g" "${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf"
 
-  ln -sf ${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf /etc/nginx/sites-enabled/server.conf
+  ln -sf "${CONTAINER_SERVICE_DIR}/nginx/assets/config/server.conf" /etc/nginx/sites-enabled/server.conf
 
-  touch $FIRST_START_DONE
+  touch "${FIRST_START_DONE}"
 fi
-
-exit 0
diff --git a/image/service/railsserver/process.sh b/image/service/railsserver/process.sh
index d71c119..703d318 100755
--- a/image/service/railsserver/process.sh
+++ b/image/service/railsserver/process.sh
@@ -4,5 +4,5 @@
 # https://github.com/osixia/docker-light-baseimage/blob/stable/image/tool/log-helper
 log-helper level eq trace && set -x
 
-cd ${ZAMMAD_DIR}
-exec gosu ${ZAMMAD_USER}:${ZAMMAD_USER} bundle exec rails server puma -b 127.0.0.1 -p 3000 -e ${RAILS_ENV}
+cd "${ZAMMAD_DIR}"
+exec gosu "${ZAMMAD_USER}":"${ZAMMAD_USER}" bundle exec rails server puma -b 127.0.0.1 -p 3000 -e "${RAILS_ENV}"
diff --git a/image/service/railsserver/startup.sh b/image/service/railsserver/startup.sh
index 0fd3a22..d88bd5c 100755
--- a/image/service/railsserver/startup.sh
+++ b/image/service/railsserver/startup.sh
@@ -6,13 +6,13 @@ log-helper level eq trace && set -x
 
 FIRST_START_DONE="${CONTAINER_STATE_DIR}/docker-railsserver-first-start-done"
 # container first start
-if [ ! -e "$FIRST_START_DONE" ]; then
+if [ ! -e "${FIRST_START_DONE}" ]; then
 
-  cd ${ZAMMAD_DIR}
+  cd "${ZAMMAD_DIR}"
 
   if [ -n "${ZAMMAD_MEMCACHED_HOST}" ]; then
     log-helper info "Memcached config..."
-    sed -i -e "s/.*config.cache_store.*file_store.*cache_file_store.*/    config.cache_store = :dalli_store, '${ZAMMAD_MEMCACHED_HOST}:11211'\n    config.session_store = :dalli_store, '${ZAMMAD_MEMCACHED_HOST}:11211'/" ${ZAMMAD_DIR}/config/application.rb
+    sed -i -e "s/.*config.cache_store.*file_store.*cache_file_store.*/    config.cache_store = :dalli_store, '${ZAMMAD_MEMCACHED_HOST}:11211'\n    config.session_store = :dalli_store, '${ZAMMAD_MEMCACHED_HOST}:11211'/" "${ZAMMAD_DIR}/config/application.rb"
   fi
 
   log-helper info "Database config..."
@@ -24,13 +24,13 @@ if [ ! -e "$FIRST_START_DONE" ]; then
     ZAMMAD_DB_PASSWORD
   )
 
-  for tag in ${TO_REPLACE[@]}
+  for tag in "${TO_REPLACE[@]}"
   do
-    sed -i "s|{{ ${tag} }}|${!tag}|g" ${ZAMMAD_DIR}/config/database.yml
+    sed -i "s|{{ ${tag} }}|${!tag}|g" "${ZAMMAD_DIR}/config/database.yml"
   done
 
   for i in {30..0}; do
-    if echo "select 1;" | mysql -h ${ZAMMAD_DB_HOST} -u ${ZAMMAD_DB_USER} -p${ZAMMAD_DB_PASSWORD} ${ZAMMAD_DB_NAME}  &> /dev/null; then
+    if echo "select 1;" | mysql -h "${ZAMMAD_DB_HOST}" -u "${ZAMMAD_DB_USER}" -p"${ZAMMAD_DB_PASSWORD}" "${ZAMMAD_DB_NAME}"  &> /dev/null; then
       break
     fi
     echo $?
@@ -44,34 +44,32 @@ if [ ! -e "$FIRST_START_DONE" ]; then
   fi
 
   # test is zammad is installed
-  ZAMMAD_INSTALLED=$(mysql -h ${ZAMMAD_DB_HOST} -u ${ZAMMAD_DB_USER} -p${ZAMMAD_DB_PASSWORD} ${ZAMMAD_DB_NAME} -e "select id from settings where name='es_url'" || true)
+  ZAMMAD_INSTALLED=$(mysql -h "${ZAMMAD_DB_HOST}" -u "${ZAMMAD_DB_USER}" -p"${ZAMMAD_DB_PASSWORD}" "${ZAMMAD_DB_NAME}" -e "select id from settings where name='es_url'" || true)
   if [ -n "${ZAMMAD_INSTALLED}" ]; then
     log-helper info "Update database..."
-    bundle exec rake db:migrate &> /dev/null
+    bundle exec rake db:migrate | log-helper debug
   else
     log-helper info "Init database..."
-    bundle exec rake db:create
-    bundle exec rake db:migrate
-    bundle exec rake db:seed
+    bundle exec rake db:create | log-helper debug
+    bundle exec rake db:migrate | log-helper debug
+    bundle exec rake db:seed | log-helper debug
   fi
 
   log-helper info "Elasticsearch config..."
-  bundle exec rails r "Setting.set('es_url', '${ZAMMAD_ELASTICSEARCH_URL}')"
+  bundle exec rails r "Setting.set('es_url', '${ZAMMAD_ELASTICSEARCH_URL}')" | log-helper debug
 
   if [ -n "${ZAMMAD_ELASTICSEARCH_USER}" ] && [ -n "${ZAMMAD_ELASTICSEARCH_PASS}" ]; then
-    bundle exec rails r "Setting.set('es_user', \"${ZAMMAD_ELASTICSEARCH_USER}\")"
-    bundle exec rails r "Setting.set('es_password', \"${ZAMMAD_ELASTICSEARCH_PASS}\")"
+    bundle exec rails r "Setting.set('es_user', \"${ZAMMAD_ELASTICSEARCH_USER}\")" | log-helper debug
+    bundle exec rails r "Setting.set('es_password', \"${ZAMMAD_ELASTICSEARCH_PASS}\")" | log-helper debug
   fi
 
-  bundle exec rake searchindex:rebuild || true
+  bundle exec rake searchindex:rebuild | log-helper debug || true
 
   log-helper info "Fix file ownership..."
-  chown -R ${ZAMMAD_USER}:${ZAMMAD_USER} ${ZAMMAD_DIR}
+  chown -R "${ZAMMAD_USER}":"${ZAMMAD_USER}" "${ZAMMAD_DIR}"
 
   log-helper info "Delete logs..."
-  find ${ZAMMAD_DIR}/log -iname *.log -exec rm {} \;
+  find "${ZAMMAD_DIR}/log" -iname "*.log" -exec rm {} \;
 
-  touch $FIRST_START_DONE
+  touch "${FIRST_START_DONE}"
 fi
-
-exit 0
diff --git a/image/service/scheduler/process.sh b/image/service/scheduler/process.sh
index 315d450..2570b42 100755
--- a/image/service/scheduler/process.sh
+++ b/image/service/scheduler/process.sh
@@ -6,5 +6,5 @@ log-helper level eq trace && set -x
 
 sv start /container/run/process/railsserver || exit 1
 
-cd ${ZAMMAD_DIR}
-exec gosu ${ZAMMAD_USER}:${ZAMMAD_USER} bundle exec script/scheduler.rb run
+cd "${ZAMMAD_DIR}"
+exec gosu "${ZAMMAD_USER}":"${ZAMMAD_USER}" bundle exec script/scheduler.rb run
diff --git a/image/service/websocket/process.sh b/image/service/websocket/process.sh
index 1380d5b..baac9e2 100755
--- a/image/service/websocket/process.sh
+++ b/image/service/websocket/process.sh
@@ -6,5 +6,5 @@ log-helper level eq trace && set -x
 
 sv start /container/run/process/railsserver || exit 1
 
-cd ${ZAMMAD_DIR}
-exec gosu ${ZAMMAD_USER}:${ZAMMAD_USER} bundle exec script/websocket-server.rb -b 127.0.0.1 -p 6042 start
+cd "${ZAMMAD_DIR}"
+exec gosu "${ZAMMAD_USER}":"${ZAMMAD_USER}" bundle exec script/websocket-server.rb -b 127.0.0.1 -p 6042 start