Apple released the developer beta for iOS 15.4 yesterday. The highlight feature is that Face ID will finally work with face masks, which is a huge deal. This has been a major irritant for iPhone users since the pandemic started (especially if you use Apple Pay, which requires your PIN twice).
But another tidbit that's come out since is that the iPhone 13 Pro's 120Hz ProMotion feature will finally work with third-party apps. For reference, it's been broken since the phone launched in September in case you've noticed that things don't look quite right on your iPhone 13 Pro or iPhone 13 Pro Max.
Christian Selig, the developer for Apollo — perhaps the best Reddit app on iOS — confirmed this on Twitter. He said that Apple told him that iOS 15.4 would fix ProMotion. He also provided a screenshot of results from his testing, showing a 8.33 ms response time, which lines up with the 120Hz refresh rate.
Yay, got a little message from someone at Apple today that this is fixed in the iOS 15.4 betas and all apps automatically get 120 Hz animations on supported iPhones going forward, and just confirmed myself. (See attached, 1/120 = 8.33 ms) 🥳🥳🥳 https://t.co/EtZ9zkrM6S pic.twitter.com/04cl8uLb11January 27, 2022
He, however, notes in a later tweet that some animations still process at 60Hz, unlike some iPads which operate at 120Hz always. This is probably a battery-saving measure by Apple, since not all animations need the full 120 frames per second. iPhones have much smaller batteries than iPads, and are likely used more often throughout the day than a tablet.
This also spells good news for the iPhone 14 Pro later this year, which we fully expect will continue the ProMotion push — 120Hz on an iPhone is a fantastic experience when it works right. Apple said some time ago that there was a Core Animation bug in iOS 15 that broke ProMotion in third-party apps. The company said the fix would come in a later update, and here we are.
Obviously, there's still a little while to wait for new version to land in the stable channel (it's not even in public beta yet), but iPhone 13 Pro owners have just one more thing to look forward to once iOS 15.4 releases. In the meantime, we've got a guide to all the changes coming in iOS 15.4 based on the initial beta.