Some time ago, I read an article that all messenger apps, by EU directive, would have to build bridge protocols in order to have flow of communication between different networks.

Surfing the web, I read an article from 2016 where the Signal protocol was being integrated into Whatsapp. More recently, I read that Signal and Telegram could communicate.

What is the true status on this? The more I search, the more contradicting information I seem to find.