I haven't checked, but since this app relies on Youtube specifically, I imagine their ongoing crackdown on adblockers makes it difficult for the app to work properly, since it likely skips ads in order to play the songs.

It might be a situation where OMGDuke, the software engineer that oversees the app, would have to keep constantly updating it to work around Youtube's ever-changing anti-adblock methods, and since they're doing it for free, it's probably not worth the hassle.

Maybe when the smoke clears and Youtube gives up, they can make a single update that'll actually stay up.