diff --git a/Dockerfile b/Dockerfile
index 232d692..d7d321c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,5 @@
-ARG PHP_VERSION=7.2-rc
-FROM php:${PHP_VERSION}-alpine
+FROM php:7.2-rc-alpine
 
-ARG PHP_VERSION
 ARG DOCKER_COMPOSE_VERSION=1.15.0
 ARG RANCHER_COMPOSE_VERSION=0.12.5
 ARG RANCHERIZE_HOME=/home/rancherize