Yak & Co Art Director Mark White (known for the adventure game Agent A) said his team weathered the asset transition well, and he framed it as a lesson that you should always expect the unexpected and implement accordingly. "We made the conscious effort early on to design things in a very flexible way because you really just can’t predict what kind of resolutions or screen shapes we’ll be running in the future," he said.
But resolution has changed on the iPhone before without major event. The iPhone X makes three additional changes that developers haven't had to contend with before. The corners are rounded, whereas other iPhones have had corners with right angles. There’s the controversial notch—Apple calls it the sensor housing—an intrusion of the camera and other hardware into the middle of the top of the screen. And finally, there's also a new indicator in the UI that is ever present at the bottom of the screen.
The home indicator
iPhone apps used to have the entire screen to themselves most of the time—the only exceptions were the status bar and notifications—but that's no longer the case. They have to cede real estate to the notch at the top and the home indicator at the bottom.
Apple already offered a set of rules and tools called Auto Layout to help iOS developers avoid potential pitfalls with using blocked-off real estate on prior iOS devices. The company describes it this way: