@Tutanota great updates! Something I've been curious about and holding me back from your calendar is event invites. This is because I struggled to make them work with other open source calendars previously and I'm highly skeptical of digital calendars (even though I'd like to break away from Google).

For example, I tested out a CalDav server as well as Murena calendar quite extensively last year and was disappointed that when inviting others or being invited. I don't like email notifications in general, but not even those would send most of the time and when they did I had to manually download the calendar event and add it. Is this similar to how calendar invites work on Tuta calendar?