diff --git a/requirements/common.txt b/requirements/common.txt
index 2952f9e..03796bf 100644
--- a/requirements/common.txt
+++ b/requirements/common.txt
@@ -1,4 +1,4 @@
-celery
+celery>4.4,<5.0
 Django==1.11.29
 django-appconf
 django-assets
diff --git a/t/Dockerfile b/t/Dockerfile
index ce5843d..d4e144c 100644
--- a/t/Dockerfile
+++ b/t/Dockerfile
@@ -5,7 +5,7 @@ FROM docker.mgm.sipwise.com/sipwise-buster:latest
 # is updated with the current date. It will force refresh of all
 # of the base images and things like `apt-get update` won't be using
 # old cached versions when the Dockerfile is built.
-ENV REFRESHED_AT 2020-04-02
+ENV REFRESHED_AT 2020-10-12
 
 # test execution; we need the backport of python3-junitxml from our own
 # repository since it's not part of Debian/buster