diff --git a/core/Dockerfile b/core/Dockerfile
index 7900be0..a07adcc 100644
--- a/core/Dockerfile
+++ b/core/Dockerfile
@@ -17,6 +17,7 @@ RUN apk update \
                    mailman==3.3.3 \
                    mailman-hyperkitty==1.1.0 \
                    pymysql \
+                   'sqlalchemy<1.4.0' \
     && apk del build-deps \
     && adduser -S mailman