diff --git a/3.3/onbuild/Dockerfile b/3.3/onbuild/Dockerfile
index b200ef8e3..dedfdaf87 100644
--- a/3.3/onbuild/Dockerfile
+++ b/3.3/onbuild/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.3
+FROM python:3.7
 
 RUN mkdir -p /usr/src/app
 WORKDIR /usr/src/app