UIDevice.orientationDidChangeNotification works as expected without calls to beginGeneratingDeviceOrientationNotifications() and endGeneratingDeviceOrientationNotifications() but the respective documentation for these two methods state:
You must call this method before attempting to get orientation data from the device.
and
You call this method after a previous call to the beginGeneratingDeviceOrientationNotifications() method.
Were they a requirement at one time and never deprecated?