diff --git a/.circleci/config.yml b/.circleci/config.yml
index 523b015..feda1c8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -2,7 +2,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: circleci/python:3.9-stretch-browsers
+      - image: circleci/python:3.7.9-stretch-browsers
     steps:
       - checkout
       - restore_cache:
diff --git a/Dockerfile b/Dockerfile
index fb71c6d..7206943 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.9
+FROM python:3.7.9
 
 WORKDIR /app
 COPY . .