Ohps…I think there was a misunderstanding by my side…
The CalDAV/CardDAV support on our internal roadmap is not what you intended, it’s the other way : support for external CalDAV/CarDAV accounts to be added as WT5 calendars/contacts resources.
Actually I don’t remember the real reason why we ditched the implementation of the CalDAV/CardDAV server components in WT5. I will double-check this.
Anyway, we may discuss about putting it back in the roadmap, if there are good reasons for it.