One of the biggest new features exclusive to the iPhone 13 Pro and iPhone 13 Pro Max this year is the inclusion of high-refresh rate displays, or what Apple calls “ProMotion.”
That means the iPhone 13 Pro models feature new OLED displays that can refresh their screen content at up to 120 times per second, or 120Hz. However, developers receiving their phones today have discovered that, in many circumstances, their animations can only run at 60Hz — the same as the cheaper iPhone 13 and iPhone 13 mini, as well as prior iPhone generations.
As it stands with iOS 15.0, ProMotion takes effect in third-party apps when scrolling or doing full-screen transitions. That means that you will still get a very fluid and responsive experience when scrolling your Twitter timeline, for instance.
However, almost all other animations are capped at 60Hz in third-party apps. This includes special effects and animations for custom components. It can be particularly jarring for the same third-party app to feature smooth scrolling but then less-smooth interaction experience elsewhere. Developer of the Apollo Reddit client Christian Selig has already reported complaints about this from his customers.