“Messenger, however, has a long history of storing people’s messages for them so that they can access them whenever they need without having to store them locally.”
Messenger shipped opt-in encrypted chats in 2016 and Zuckerberg promised encryption everywhere in 2019. Default encryption for personal chats starts rolling out now, four years later. Message history still sits on Meta’s servers, now under a new protocol called Labyrinth with keys Meta says users control. Meta still holds every message. The change is that it now promises not to be able to read them.