diff --git a/Dockerfile b/Dockerfile
index be69bc2..1fcde7f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian:trixie
+FROM debian:trixie-20260316
 
 RUN apt-get update && \
     apt-get install -y postfix libsasl2-modules mailutils opendkim opendkim-tools && \