Also for me, having everything online makes the calendar very slow.
Each time I change the view, add an event, etc... I have to wait 2-3 seconds.
It is very sloppy.

I tried the Proton Calendar for one day and I went back to Fossify Calendar, which doesn't need internet at all and is very fast because all data is local.

This is a serious shortcoming for a calendar. At very least being able to always see the calendar even when connection lost or poor should be possible. I have noticed recently a few occasions where I am trying to view and make new entry and the calendar entries are 'reloaded' bit by bit as, I watch rather than just being persistent.

I'd consider this functionality a core component, not a mere feature.

I work often in a train, it's HORRIBLE. Sometimes I think about alternative to Proton Calendar. I hope this functionality will come soon.

The modification and creating of events offline is a must. I fully support the request.

Proton, do you foresee this vital function one day?

This is also critical because of the (lack of) performance this implies. Currently the simple act of saving a calendar entry takes up 1 second or more, which maybe would have been acceptable using a 64kbit/s modem in the late 90es. But it is unaccetable in 2025.

Actually really frustrating that this is not possible. This should be the most basic feature of a calendar app. Personally this is even more important than several other features already implemented

This should not be a feature request, it should be a function of the calendar at version 1.0

I see this as a problem by Proton being a "privacy assurance first" issue of being always online, but an option where we can set a trusted device to have offline access is a must.

VERY important. This feature is a real brake on the use of the mobile app.

Yes this. Generally Offline Support would be good. I cant open the App in Airplane mode. That needs to be implemented.