diff --git a/Dockerfile b/Dockerfile
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,7 +22,7 @@
 RUN python3 -m venv /srv/softwareheritage/venv
 ENV PATH="/srv/softwareheritage/venv/bin:${PATH}"
 RUN pip install --upgrade pip setuptools wheel
-RUN pip install gunicorn==19.9.0
+RUN pip install 'gunicorn<20'
 
 RUN pip install \
         swh-core[db,http] \