As per apple documents apps running in background cannot receive callbacks except for apps which are location based, VOIP, Newstand, Music player or APNS enabled. How to receive the connection status callbacks in that case? The app is making use of AVAudioSession instance as:
try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord, with:AVAudioSessionCategoryOptions.allowBluetooth)
And listens to notifications as:
NotificationCenter.default.addObserver(self,selector:#selector(handleRouteChange), name: .AVAudioSessionRouteChange,object: AVAudioSession.sharedInstance())
This is called in the launch of the application.