The upgrade instructions can be found in the README.txt. After loading the new files accessing the xCMS admin section will prompt you with necessary changes and provide an SQL patch that needs to be applied.
Applying the SQL differences directly will prevent this from displaying the needed file changes. If you had xCMS installed prior to upgrading, you will still need to make those additional file changes. If you submit a ticket to
https://www.websitecm.com/support/ I can send you those file changes.