This is a reasonably critical issue for me since I rely heavily on my calendar in daily life. I need to sync the calendar across mobile and desktop. I'm considering whether or not to renew my Protonmail subscription without this feature.

I am already using the Proton Mail Bridge to use my favorite MUA; if CalDav could be integrated into that existing - and perfectly working! - product, that'd be really great.

I love the security of ProtonMail, and the UI for email and the calendar are very user-friendly. However, I have found the lack of CalDav support to bring all my calendars together in one place makes the service unusable. When my subscription is up, I'll begrudgingly move over to iCloud.

Diese CalDav-Funktion wäre für mich essentiell, um endgültig den Proton-Kalender als Hauptkalender zu benutzen.

CalDav for  please.

this feature is really desperately needed

I actually signed up not even realizing this wasn't implemented yet. Lucky me, I was about to go for the yearly version but at the last moment decided to give it a month for a trial run. Is there any roadmap for this feature?

I am not very familiar with using digital calendars. I would like to sync my Proton Calender with the CalDav-supporting App on my phone.

Is this possible?

This is a mandatory option for my business. I can't contemplate migrating to Proton services until there is a CalDav option - this is as fundamental as IMAP. The web UI is great and all, but I do not operate in a single-vendor environment, nor does anyone I know. Even if CalDav was just available via VPN only, that would work (as a possible compromise.)