Whatsapp did a revamp of their web client a few years ago. The previous version pretty much connected to your phone and proxied all send/receive message reques

Whatsapp did a revamp of their web client a few years ago. The previous version pretty much connected to your phone and proxied all send/receive message requests via your phone. The phone stored all the crypto keys etc for e2e. The new version acts as a fully fledged client. All "1:1" chats are in fact group chats, containing multiple 'users' for all of your devices, and multiple users for all of the other persons devices. Cryptography is still e2e secure, but now there are n+m endpoints for all of your+their devices. Therefore, I would expect major updates to be needed to this client to make it continue to work.