diff --git a/docker/sympa/Dockerfile b/docker/sympa/Dockerfile
index b9e3c3d596111b1535bc75998d57ad7e4af532d4..2d1ec7d095986d597ec986a874803bd7821393cf 100644
--- a/docker/sympa/Dockerfile
+++ b/docker/sympa/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian:buster
+FROM debian:bullseye
 
 ENV DEBIAN_FRONTEND noninteractive