Nondestructive Upgrading of Jenkins on Tomcat

[Jesse McCormick]

Previously I have used standalone Jenkins installations, and it was simple to use the Jenkins web-ui to initiate an upgrade to the latest Jenkins version.

Now I am running Jenkins 2.14 on a Tomcat 8 installation. I have read to the documentation here: https://wiki.jenkins-ci.org/display/JENKINS/Tomcat

If I replace the old war file with the new war file, Tomcat re-deploys the application and Jenkins reverts to initial setup mode. How can I upgrade versions without having to reconfigure Jenkins after the update?