Well, this is the consequence of Telegram's poor privacy choices. Most chats are not end-to-end encrypted, and they could have access to their content. This makes them liable when they refuse governments' requests for such information. It also raises the question of whether they have given such access to other governments like Russia (coincidentally, Durov was in Baku at the same time Putin was visiting, and there is speculation that they may have met).
In contrast, Signal does not have access to any chats or user information (except the timestamp of when users last logged in) and could not be forced to wiretap.
Couldn't they just quietly release an update, under a threat of a 20y jail time, or just $5 wrench? Any centralized solution is vulnerable. The only real solution is open source serverless p2p network.
Well, maybe in russia but not in the USA. At least not yet. Check the history of PGP as an example of strong encryption the government was not happy about.
In contrast, Signal does not have access to any chats or user information (except the timestamp of when users last logged in) and could not be forced to wiretap.