Syncing with mailbox.org thru WebDAV is possible from Open-Xchange 7.10.2 and I have been using it for about 2 months and very happy.
After upgrading Joplin to version 1.0.193 on all of my devices (Linux, Linux CLI, Windows and iOS 10.0.45) the sync stopped working. Error message reads as:
MKCOL .sync/: Unknown error 2 (409)
I also posted this issue on mailbox.org support forum (my comment shows up as 9842272)
There's no such call in Joplin. "MKCOL .sync/" yes, but not ".sypc/".
Sorry, it’s a typo. I also checked my iOS version, and it should be 10.0.45
For the time being I switched to Dropbox sync, but would love to see a solution for mailbox.org