diff --git a/Dockerfile b/Dockerfile
index d206446..9d1048d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,7 @@ RUN apt-get update -y && apt-get upgrade -y && apt-get install -y maven git
 
 WORKDIR /
 # TODO freeze revision?
-RUN git clone https://github.com/ad-freiburg/pdfact.git
+RUN git clone https://github.com/ad-freiburg/pdfact.git --depth 1 --branch master
 WORKDIR pdfact
 
 RUN mvn install -DskipTests