diff --git a/docker-compose-separate-containers.yml b/docker-compose-separate-containers.yml
index 18b1e46..90230e0 100644
--- a/docker-compose-separate-containers.yml
+++ b/docker-compose-separate-containers.yml
@@ -1,4 +1,4 @@
-version: '3'
+version: '2.1'
 services:
   nginx:
     image: nginx