diff --git a/postgres-backup-s3/Dockerfile b/postgres-backup-s3/Dockerfile
index 7dffc14..59014f9 100644
--- a/postgres-backup-s3/Dockerfile
+++ b/postgres-backup-s3/Dockerfile
@@ -1,8 +1,6 @@
 FROM alpine:3.7
 LABEL maintainer="Johannes Schickling <schickling.j@gmail.com>"
 
-ARG DOCKER_API_VERSION
-
 ADD install.sh install.sh
 RUN sh install.sh && rm install.sh