Generic CalDAV integration [FEATURE REQUEST]

Please consider supporting or integrating with CalDAV-based online calendars.

At the moment, only and Nextcloud-based calendars using this protocol are supported, but there's a growing need for broader CalDAV integration, and here’s why:

Many hosting providers - especially those offering cPanel - include CalDAV (and CardDAV for contacts) as part of their webmail solutions. Each user with a custom mail account on platforms like cPanel/Roundcube would benefit from seamless integration with CalDAV calendars.

In addition, widely used business mail servers such as Communigate, Kerio Mail, Open-XChange, and Zimbra also offer CalDAV-based calendars. These solutions are increasingly popular among local authorities & governments, SMEs, and organizations seeking alternatives to Google or Microsoft services - especially within the EU, where data privacy is a major concern.

Using CalDAV-based calendars enhances privacy by keeping user data off US-based platforms, supports native integration with desktop and mobile calendar apps through open protocols, and typically includes key groupware features such as sharing and notifications.

Supporting standard CalDAV would not only expand compatibility across a wide range of platforms but also align with growing demand for open, privacy-focused alternatives.

As far as I know, none of the other calendly-alternatives - I already evaluated Amelia, Bookly, BookingPress, Booknetic, LatePoint, MotoPress Appt. Booking and Timetics) - support generic CalDAV, so I'm sure this integration would definitely help you grow your user-base as well :)