The .zip from the Webpage
Edit: Just tried the Version from Github and it seems to work. Before my Upgrade i got a lot DB Error Mails and Entrys in Systemlog like these:
Table 'bs_faculty_tickettest.ost_group_dept_access' doesn't exist
http://tickettest.n-faculty.de/scp/ajax.php/upgrader
But OSTicket postet this Message after updating:
Upgrade Completed!
Congratulations! osTicket upgrade has completed successfully.
Please refer to Release Notes for more information about changes and/or new features.
Now i am testing.