The Signal Server repository hasn’t been updated since April 2020. There are a bunch of links about this here but I found this thread the most interesting.
To me, this is unforgivable behaviour. Signal always positioned themselves as “open source”, and the Server itself is under the best license for server software (AGPLv3 – which raises questions about the legality of this situation).
Signal’s whole approach to open source has constantly been underwhelming to say the least. Their budget-Apple attitude (secrecy, i.e. “we can never engage the community directly”, “we will never merge/accept PRs”, etc) has lead to its logical conclusion here, I guess. I have been somewhat of a “Signal apologist” thus far (I almost always defend them & I think a lot of criticism they get it very unfair) but yeah I’m over Signal now.
FluffyChat is a decent alternative client (with E2EE support). If you don’t need e2ee there’s actually a healthy number of clients, and some of them do seem to have it on their roadmap
https://matrix.org/clients/
Point taken on server implementations though
FluffyChat is not an option because it doesn’t support proxies including Tor. If you’re using fluffychat please open an issue there for integrated tor support like Conversations/Gajim does in the Jabber/XMPP world :)