Author here.

I haven't seen any evidence of Spotify killing librespot. To me the project looks active and works totally fine. I don't have a new Spotify account to verify the claim above.

I suspect wilted-iris is conflating it with the recent changes to the Web APIs: new developer apps can't use all endpoints anymore. In Fastpotify if you add your Client ID I use both an older developer app and your app to keep everything as fast and seamless as possible.