Update Dockerfile
diff --git a/Dockerfile b/Dockerfile
index 6932d26..91a7641 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -21,11 +21,11 @@
 
 COPY init.groovy /usr/share/jenkins/ref/init.groovy.d/tcp-slave-angent-port.groovy
 
-ENV JENKINS_VERSION 1.596.1
+ENV JENKINS_VERSION 1.596.2
 
 # could use ADD but this one does not check Last-Modified header 
 # see https://github.com/docker/docker/issues/8331
-RUN curl -L http://mirrors.jenkins-ci.org/war-stable/1.596.2/jenkins.war -o /usr/share/jenkins/jenkins.war
+RUN curl -L http://mirrors.jenkins-ci.org/war-stable/$JENKINS_VERSION/jenkins.war -o /usr/share/jenkins/jenkins.war
 
 ENV JENKINS_UC https://updates.jenkins-ci.org
 RUN chown -R jenkins "$JENKINS_HOME" /usr/share/jenkins/ref