No need to update the Config (if you already have since 1.6.0). Just grab the Update and replace in your Plugins directory.
Changelog:
Fixed that /unguest or /guestmode:unguest now returns a message that you have to add a Playername for it to work. This fixes a "null" error in console/log because we can't unguest "nothing". Thanks for reporting Turboline!
Just some small codestyle improvements here and there, too.