diff --git a/containers/zammad/docker-entrypoint.sh b/containers/zammad/docker-entrypoint.sh
index 7917a42..62a87de 100755
--- a/containers/zammad/docker-entrypoint.sh
+++ b/containers/zammad/docker-entrypoint.sh
@@ -21,6 +21,7 @@ set -e
 : "${ZAMMAD_WEBSOCKET_HOST:=zammad-websocket}"
 : "${ZAMMAD_WEBSOCKET_PORT:=6042}"
 : "${NGINX_SERVER_NAME:=_}"
+: "${RSYNC_ADDITIONAL_PARAMS:=--no-perms --no-owner}"
 
 function check_zammad_ready {
   sleep 15
@@ -34,8 +35,10 @@ function check_zammad_ready {
 if [ "$1" = 'zammad-init' ]; then
   # install / update zammad
   test -f "${ZAMMAD_READY_FILE}" && rm "${ZAMMAD_READY_FILE}"
-  rsync -a --delete --exclude 'public/assets/images/*' --exclude 'storage/fs/*' "${ZAMMAD_TMP_DIR}/" "${ZAMMAD_DIR}"
-  rsync -a "${ZAMMAD_TMP_DIR}"/public/assets/images/ "${ZAMMAD_DIR}"/public/assets/images
+  # shellcheck disable=SC2086
+  rsync -a ${RSYNC_ADDITIONAL_PARAMS} --delete --exclude 'public/assets/images/*' --exclude 'storage/fs/*' "${ZAMMAD_TMP_DIR}/" "${ZAMMAD_DIR}"
+  # shellcheck disable=SC2086
+  rsync -a ${RSYNC_ADDITIONAL_PARAMS} "${ZAMMAD_TMP_DIR}"/public/assets/images/ "${ZAMMAD_DIR}"/public/assets/images
 
   until (echo > /dev/tcp/"${POSTGRESQL_HOST}"/"${POSTGRESQL_PORT}") &> /dev/null; do
     echo "zammad railsserver waiting for postgresql server to be ready..."