They work already! When I add my email account, Thunderbird automatically configure my email, my calendar, my contacts, my tasks... all from my server. I even don't have to configure them each one manually.
Really? Wow! Ive never been able to get everything from fastmail to come over correctly. My calendars were read only and I didnt get full contact info.
I've been using both those features for a while with my own Nextcloud server
Yes but you need tbsync to use it with nextcloud cal/carddav no?
I don't have tbsync and I don't think any other extension I use added support for that.
Simply select "On the Network" when adding a calendar, set a user name and enter the remote dav location.
For address books use "Add CardDAV Address Book", also username and dav location.