diff --git a/containers/zammad/Dockerfile b/containers/zammad/Dockerfile
index 197abfb..20baa8d 100644
--- a/containers/zammad/Dockerfile
+++ b/containers/zammad/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.3.1-slim
+FROM ruby:2.4.1-slim
 MAINTAINER Zammad <info@zammad.org>
 ARG BUILD_DATE