Problem with the caldav sync after upgrade to 19.0.0


after upgrading to 19.0.0 I realize a problem with the caldav sync. does not work any more. Beside this there is a message complaining about an incorrect setup /.well-known/caldav is not reachable.
Well there was no change at all, it worked since month. The issue came with the update. I double checked the settings in .htaccess there obviously have been changes but the redirect rules for /.well-known/caldav seem to be the same as before.

Does anyone know how to get that to work again?