Hey Garry, When Gmod 13 releases, Which User data is going to be transferred? I mean, When gmod 13 releases we will have our maps and addons from gmod 12? or gmod 13? or BOTH?

When we move over it will be like any other update. So all of your addons and whatever will still exist underneath. Some of these will work, most of them will have errors. Maps should still exist there – and should work no problem. Saves and demos probably won’t work.