diff --git a/Dockerfile b/Dockerfile
index d4bf5f2..6e126aa 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 ARG VERSION=latest
-FROM tomsquest/docker-radicale:$VERSION
+FROM tomsquest/docker-radicale:3.1.9.1
 
 RUN python3 -m pip install --upgrade https://github.com/Unrud/RadicaleInfCloud/archive/master.tar.gz
 COPY config.js /usr/lib/python3.7/site-packages/radicale_infcloud/web/config.js