diff --git a/Dockerfile b/Dockerfile
index 882a4e0..bdc7aa9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,7 @@
 FROM debian:stretch
 EXPOSE 34197/udp
 
+# you can configure this by passing --build-arg=FACTORIO_VERSION=0.17.79
 ARG FACTORIO_VERSION=0.17.79
 
 ADD bin/entrypoint.sh /entrypoint.sh