diff --git a/environment.worker.yml b/environment.worker.yml
index f36d877b0..e17c6110d 100644
--- a/environment.worker.yml
+++ b/environment.worker.yml
@@ -3,5 +3,5 @@ dependencies:
   - python=3.7
   - pip:
       - pillow
-      - matplotlib
+      - matplotlib==3.2.2
       - simplejson