With calendar birthday adapter app it works
On Roundcube I created a second calendar, which I deleted a while after that.
I synced both with DAVdroid to my Android phone and to my calendar on OSX.
When I deleted one calendar it was also gone on OSX but DAVdroid still tried to sync it.
Duplicate of #243. At the moment, DAVdroid doesn’t check for deleted or new collections but synchronizes the ones set up.