I really delete the calendar from DavDroid.
But you’re right, now I have the confirmation dialogue:
Well … I do not understand, my version was downloaded recently on F-droid. The most important thing is that it works now, thanks rfc2822 !
I just wrote a quick screenshot tutorial on setting up Hubzilla CalDAV with DAVdroid and Copy Contacts on Android. It’s at HOWTO Hubzilla CalDAV with DAVdroid and Copy Contacts