diff --git a/testserver/docker_uffd/templates/Dockerfile-release b/testserver/docker_uffd/templates/Dockerfile-release
index feaaa98add6801d43b3a615b3e861541be492ea1..375f1edae515f02bf4af593363d1f20949d4a61c 100644
--- a/testserver/docker_uffd/templates/Dockerfile-release
+++ b/testserver/docker_uffd/templates/Dockerfile-release
@@ -1,4 +1,4 @@
-FROM debian:bullseye
+FROM debian:bookworm
 
 ENV DEBIAN_FRONTEND=noninteractive
 
diff --git a/webserver/docker_uffd/templates/Dockerfile-release b/webserver/docker_uffd/templates/Dockerfile-release
index feaaa98add6801d43b3a615b3e861541be492ea1..375f1edae515f02bf4af593363d1f20949d4a61c 100644
--- a/webserver/docker_uffd/templates/Dockerfile-release
+++ b/webserver/docker_uffd/templates/Dockerfile-release
@@ -1,4 +1,4 @@
-FROM debian:bullseye
+FROM debian:bookworm
 
 ENV DEBIAN_FRONTEND=noninteractive