To support much-requested features like tasks, search capabilities, and offline access, we’ve started work on our next generation of Proton Calendar apps for iOS and Android, which we aim to release toward the end of 2025.
I think this bit excited me the most. Tasks and offline access would be super useful to me.
I do hope one day, Microsoft provides better syncing with Proton. It takes hours (after the initial sync) if I want to sync my work calendar with my Proton calendar.
Exactly. These are the main reasons I haven’t seriously considered Proton Calendar yet.
In order to avoid duplicating effort, we have been building new features directly into the new app so we can bring you the new app faster
Seems we need to wait at least 1 year for features like tasks and offline mode. 
Normally they never provide a timeline or a tentative release date for anything so let’s be grateful we got some concrete news about future improvements.
yeah, although without fixing the syncing issues I mentioned (which I think are outside of Protons control), even if these were implemented today, the usability for myself would not increase that much sadly.