SOLVED With iOS 10.2 AirPlay button has reappeared and it still works. Apple poltergeist!
In iOS 9 I used this code to detect Airplay devices. With deployment target 10.00 it doesn't appear. In Control Center I can find my airplay devices, but in my app the uiview doesn't show anything. In my capabilities I have checked under "background mode", Audio, AirPlay and picture in picture. Maybe I forget some new setting of this blessed sandbox? Thanks for your patience
@property (weak, nonatomic) IBOutlet UIView *airplay;
MPVolumeView *myVolumeView = [[MPVolumeView alloc] initWithFrame: airplay.bounds];
[myVolumeView setShowsVolumeSlider:NO];
[myVolumeView setShowsRouteButton:YES];
myVolumeView.transform = CGAffineTransformMakeScale(0.3,0.3);
[myVolumeView setRouteButtonImage:[UIImage imageNamed:@"myIconAirPlay"] forState:UIControlStateNormal];
[airplay addSubview: myVolumeView];