Hey
Do you mean, fetching from caldav servers? We are working on integrating local device calendars into the app so you can use especialised Caldav apps(like Davx5) to pull data from caldav into device calendars then use our app to get a unified viewed

If you mean exposing nostr calendar events over Caldav servers then no its not supported as of yet. We also have no plans atleast in the near future as the events are all encrypted by your nsec and exposing the events over Caldav would mean us asking for your nsec which we dont want to do. Although we do have some ideas on how to do it, but they are not trivial and would require a complicated setup. We will experiment with them and see what works best without compromising privacy but there is no timeline set as of now