iOS 15.4 lets iPhone apps offer ProMotion 120Hz refresh rates for all animations

Apple with iOS 15.4 has reportedly fixed a Core Animation bug that has resulted in a sub-par ProMotion experience. Now all third-party apps automatically use smooth 120Hz animations on iPhones that feature support for ProMotion display technology.

Image from Apple's YouTube video showing ProMotion technology in action, with a hand holding an iPhone 13 Pro and scrolling through a list and the title "120Hz adaptive refresh rate" overlaid on top
Image credit: Apple / YouTube
  • On iOS 15.4, all apps automatically get 120Hz animations on compatible iPhones
  • Before iOS 15.4, some but not all animations in third-party apps used ProMotion
  • This was an apparent bug in Apple’s Core Animation subsystem

iOS 15.4 fixes a bug with ProMotion in iPhone apps

With iOS 15.3 and older, some app animations would use additional frame rates and others would not. Others didn’t offer ProMotion support at all. An apparent bug with Apple’s Core Animation subsystem, it led to sub-par experiences due to visible animation inconsistencies puzzling users. With iOS 15.4, however, Apple is automatically enabling smooth 120Hz refresh rates for all custom animated content in apps.

This was confirmed by Apollo developer Christian Selig on Twitter.

He said that he received “a little message from someone at Apple today” informing him that this bug has been squished in the latest iOS 15.4 beta. Now all apps “automatically get 120Hz animations on supported iPhones going forward,” he wrote.

On the Mac side of things, the recently-launched macOS Monterey 12.2 update switched on 120Hz scrolling in Safari on ProMotion-enabled Macs.

Tell me more about ProMotion

ProMotion is Apple’s marketing name for an adaptive refresh rate technology.

ProMotion dynamically changes a display’s refresh rate to save power and provide smoother animations and video. The refresh rate may drop to as low as 10Hz when reading static content like a book, increasing to 24Hz when you’re watching a 24fps movie or hitting 60Hz when watching a 60fps YouTube video.

For games, video-focused apps and user interface animations, the refresh rate may go all the way up to 120Hz (twice the standard refresh rate of 60Hz). The refresh rate adapts in real-time, automatically, with no action required on your part.

ProMotion is supported across some, but not all Apple devices. The variable refresh rate technology is currently utilized on the iPad Pro family, the iPhone 13 Pro and iPhone 13 Pro Max and the new 14 and 16-inch MacBook Pro laptops.