diff --git a/modules/mailu/automx/Dockerfile b/modules/mailu/automx/Dockerfile
index 80ae1b9..c48cab2 100644
--- a/modules/mailu/automx/Dockerfile
+++ b/modules/mailu/automx/Dockerfile
@@ -19,7 +19,7 @@ RUN chmod u+x setupvenv.sh start add-domains setup setup-db
 
 RUN ./setupvenv.sh \
    && . .venv/bin/activate \
-   && pip install automx2
+   && pip install automx2==2021.6
 
 # The launcher `start` expects. In the predecessor's image this wrapper appeared during a build
 # step that never made it into the files this module carries — the image worked and the recipe