diff --git a/lib/worker_multibuild.py b/lib/worker_multibuild.py
index c4085eb..8f1a409 100644
--- a/lib/worker_multibuild.py
+++ b/lib/worker_multibuild.py
@@ -46,6 +46,7 @@ RUN pip3 install setuptools_rust
 RUN pip3 install 'buildbot-worker==3.1.1' \
                  'cryptography==2.1.4' \
                  'twisted==17.9.0' \
+                 'Automat==20.2.0' \
                  'pyopenssl==17.5.0'
 RUN groupadd buildbot
 RUN useradd -d /var/lib/buildbot -m -g buildbot buildbot