Perfect now it works again :) I thought i made a mistake.

I'm sorry to hesitate you again.
Today i was working on the dokuwiki and recognised, that the plugin still dont work.
After that i saw the update for webdav
I updated the webdav plugin but nothing changed.

It works now!
I updated davical from version 1.1.3 to 1.1.5 about backport package made a resync and now I see the data.
So I guess there where changes made for debian stretch.

Thanks for the quick response. Obvisily nothing changed i deleted brwoser cache etc.
Do you need access to my system?

Actual i found this at the apache error.log