diff --git a/prolog-swi-apt/Dockerfile b/prolog-swi-apt/Dockerfile
index b203a9b..f33cdb9 100644
--- a/prolog-swi-apt/Dockerfile
+++ b/prolog-swi-apt/Dockerfile
@@ -1,6 +1,7 @@
 FROM nacyot/ubuntu
 MAINTAINER Daekwon Kim <propellerheaven@gmail.com>
 
+RUN apt-add-repository ppa:swi-prolog/stable
 RUN apt-get update
 RUN apt-get install -y swi-prolog