I gonna start working on an app that have basic functionality to mute phone(no sound from any app, ring tone). I searched over net and found some private api's to do what I want.
https://github.com/forensix/BBSettings
But found some articles saying that Apple will not approve such kind of apps. And when I searched over store I got an app link below
https://itunes.apple.com/us/app/autosilent/id474777148?mt=8
This is auto silent app, that put iphone to mute state.
So now I want all my seniors to let me know whether I can do this app or not?
The application that you mentioned has the purpose of muting the phone. Someone downloading it expects it to mute the phone. That's probably why it was accepted on the store.
If your app mutes the phone, and the user didn't expect it, they could very likely miss important phone calls unexpectedly, which could be very damaging. So you would need a very, very good reason to have that functionality in your code.
来源：https://stackoverflow.com/questions/22575073/mute-iphone-prorammatically-is-legal