diff --git a/docker-compose.test.yml b/docker-compose.test.yml
index af6539b..69bc18a 100644
--- a/docker-compose.test.yml
+++ b/docker-compose.test.yml
@@ -1,4 +1,4 @@
-version: '2'
+version: '2.1'
 services:
   proxy:
     image: squidproxy