diff --git a/Docker.md b/Docker.md
index a65799a..4846acd 100644
--- a/Docker.md
+++ b/Docker.md
@@ -24,6 +24,12 @@ Make sure you have Docker installed and set up on your machine before following
 
 # Docker Compose 
 
+First make sure you have a Docker version [recent enough](https://docs.docker.com/compose/compose-file/) to support `version: 3` format:
+```bash
+docker --version
+Docker version 18.09.1, build 4c52b90    # must be >= 17.04.0
+```
+
 An example [`docker-compose.yml`](https://github.com/pirate/ArchiveBox/blob/master/docker-compose.yml) config with ArchiveBox and an Nginx server to serve the archive is included in the project root.  You can edit it as you see fit, or just run it as it comes out-of-the-box.
 
 ## Setup