title: Upgrade Jenkins CI withourt losing User/Job Config
body: <p>I would like to upgrade Jenkins to the latest version without losing job/user configuration.
  From looking through various posts the answer seems to be to replace the jenkins war directory.
  I did this and although the new version seems to be in place the about dialogue still has the original version,
  I think this is because the versionnumber is held in a config file outside of the war folder.
  Is there a better method to upgrade.</p>