I have just upgraded a website that was on version 2.0.2b to the latest version. I followed the instructions by deleting the existing folders and copying across the new 4 folders.
The existing website did not have an auth_id folder. The first time I tried upgrading I copied the 4 folders across (including auth_id). When I went to try and login it came up with a silverstripe page not found page. I played around a bit and couldn't get it to work. I then removed the auth_id folder and it seems to have upgraded fine!
My question is what is the auth_id folder for and do I need it to run SilverStripe?