pls fix asap. We do not need another (bad) calendar app from proton, we just want to use the existing (good, convenient, whatever) calendar apps that are already out there with a secure calendar backend. Don't reinvent the wheel, please, if it is not necessary :)

Bridge app is alreday able to sync email with clients such as Thunderbird. Why don't extend bridge to sync contacs and calendar too? Would be life changing feature.

This seems like a very logical extension to the Bridge concept. I want to switch my calendar to Proton, but Business Calendar on Android has features that Proton's calendar doesn't--features that I won't do without.

I would like to propose the addition of a crucial feature to enhance the use of Proton Mail on mobile devices. This feature involves synchronizing contacts and calendars on Android and iOS devices using WebDAV (Web-based Distributed Authoring and Versioning) technology.

This feature is essential for several reasons:
- It allows direct access to contacts from my phone, which is particularly useful when I need to send a message via WhatsApp or any other messaging app.
- The current absence of this feature forces me to copy and paste contact numbers each time, which is cumbersome and inefficient.
- Synchronizing contacts and calendars using WebDAV would ensure a seamless integration of my email, contacts, and calendar across all my devices.

WebDAV offers several benefits:
- It is an open standard widely supported by many email clients and contact and calendar management applications.
- It allows bidirectional synchronization, meaning changes made on one device are reflected on all other synchronized devices.
- It can be used with security protocols such as HTTPS, ensuring the confidentiality and integrity of the data transferred.

I believe this feature is essential for my daily use of Proton Mail and should be prioritized in your development roadmap.

Thank you for considering my request.

Proton Mail comes with great features like an address book (Contacts) within Proton Mail and Proton Calendar.

However, due to the privacy nature of zero knowledge (encryption), Proton cannot offer a way to provide their own CardDAV endpoint without either storing the (encrypted) secret/encryption key in their database (bad) or relying on the client to submit the secret/encryption key in every request (very bad).

I use a Nextcloud service to synchronize my contacts and appointments via CardDAV and CalDAV across several endpoint device classes. For example my dedicated VoIP phones, routers with VoIP servers inside, smartphones, and email clients.

On the smartphone there is no issue, because the Proton Mail mobile client offers a combined address book (contacts). While there is no synchronization between the Proton contacts and the smartphone contacts, the mobile app can access both.

The issue comes when using the desktop client or the web client. Here there is no combined address book (contacts). Only the Proton-native contacts are known. I can solve this via exporting my main address book as an VCard and import them in to Proton Mail contacts, but this also raises issues (mainly duplicates, and excessive personal efforts which could be used better).

My solution to the issue: Allow the Proton Mail desktop client to subscribe to an CardDAV endpoint and synchronize this endpoint (both directions) with the Proton Mail native address book (contacts).
Proton Mail desktop client should not provide an CardDAV endpoint, but consume/subscribe to an external CardDAV endpoint.

This way, I do not waste my time in manual synchronization and deduplication.

not having CardDAV will ensure i don't waste my money and renew next year. i felt dumb for not researching before i purchased. my whole point was to move away from other providers only to find out one of the simplest and critical items isn't available to sync

CalDAV is a standard protocol. It would be great for many Proton users to have this feature for those who don't have the choice of keeping a third-party calendar (e.g. professional) and for whom it is not at all practical and viable to have several applications to view their calendars separately. For many Proton users, it would be great and very practical to be able to group their calendars via the CalDAV protocol in a single application ;)