https://arstechnica.com/gadgets/2017/11/how-devs-updated-their-apps-for-the-iphone-xs-screen-and-the-notch/

The heart of the iPhone X's pitch is third-party apps. From augmented reality features to the TrueDepth sensor, the new features are meant to stir creativity and action in the developer community, bringing innovative new app experiences to iPhone X users. But even as Apple gives developers new toys to play with, it also has to make sure it doesn't break their old ones.