To upgrade: If you are running any 6.4 stable release or any 6.4-rc/6.5-rc release, click 'Check for Updates' on the Tools/Update OS page. If you are running a pre-6.4 release, click 'Check for Updates' on the Plugins page. If the above doesn't work, navigate to Plugins/Install Plugin, select/copy/paste this plugin URL and click Install: https://s3.amazonaws.com/dnld.lime-technology.com/stable/unRAIDServer.plg   Refer also to @ljm42 excellent 6.4 Update N