It seems playbackRate (https://developer.apple.com/documentation/musickitjs/musickit/player/2992760-playbackrate) does not work at anything besides 1.0 on iOS 15.4 (It still works on iPhones with older versions).
I've tried setting it in many different ways including what shown at https://developer.apple.com/forums/thread/687931
This has broken functionality in my app and others on the App Store.
Mostly I would like to bring this to Apple's attention and would like to know if this is intentional or a bug?
Hello @oneway111,
We have re-evaluated our previous decision to disable changing the playback rate for subscription content from Apple Music in third-party applications, and we came to the conclusion that we could safely enable that functionality again, just like before the release of iOS 15.4.
As such, this issue is fixed in iOS 15.5 beta 4.
I hope this helps.
Best regards,