i have a logon Problem with Error 405 from iOS App 2.25.9.2 to Nextcloud Server 12.0.2.
Could it be that the Nextcloud Version we are using is not compatible anymore with Nextcloud 12?
If yes, could you let me know if there is a direct upgrade path to Version 16 or 17 or if need a new Setup instead?
If a new Setup is necessary, is there a way to migrate the data over to the new Server?
hey @mmayr
long time no see 
so welcome back.
well nc 12.x is outdated by far and thus a major security-issue for your and your users. afaik nextcloud releases all known security glitches of outdated versions only a few weeks after they reached their EOL. so it’s no abstract thread you’re facing. it’s a real problem.
thus i’d recommend to upgrade your instance asap. the only promising way would be… doing it step by step… updating to nc 13 first… and see if there are errors in the admin section that needs to be solved. then nc 14 … after solving all admin.-error messsages --> nc 15 etc.
and don’t forget to take backups.