Spotify seems quite unstoppable right now, with the music streaming outfit will now not accept anymore submissions for its App Finder program. The App Finder program allowed developers to publish apps inside of its desktop client, but not anymore.
Looking into the future, Spotify will rel ease multiple new mobile SDKs, as well as expanding its web API with more features in the coming months. The apps that have already been published will continue to be available as they're made on Spotify's latest API 1.x framework. From here on out, those apps will only receive critical updates.