diff --git a/dockerfile/Dockerfile b/dockerfile/Dockerfile
index 202d96a156d63081b63097fa568431fc4340677e..faf5b1a45990e7a8edc836b24271dc8d024e0149 100644
--- a/dockerfile/Dockerfile
+++ b/dockerfile/Dockerfile
@@ -7,7 +7,9 @@ LABEL Description=DaCHS\ is\ a\ publishing\ infrastructure\ for\ the\ Virtual\ O
 
 MAINTAINER "Carlos Brandt <carloshenriquebrandt at gmail>"
 
-ENV PG_VERSION=9.6
+ARG PG_VERSION=9.6
+ENV PG_VERSION=${PG_VERSION}
+
 
 RUN DEBIAN_FRONTEND='noninteractive'                    && \
     apt-get update                                      && \