iPhone 13 Pro 120Hz ProMotion display requires developers to update apps

By Ewdison Then/Sept. 26, 2021 9:27 pm EST

Although some criticize the iPhone 13 for having too few noteworthy upgrades, there are definitely some notable improvements in the iPhone 13 Pro and the iPhone 13 Pro Max. One of the most significant is the ProMotion display that finally catches up to what Android phones have been doing since last year. Unfortunately, there has been some confusion about this 120Hz feature, and it will apparently require developers to put in some extra work to take advantage of the smoother animations.

Faster display refresh rates are no longer just fancy features these days, and they aren't just for gaming either. Even something as fast as a 90Hz refresh rate can improve the user experience with smoother animations and seemingly more responsive user interfaces. On Android smartphones, the feature doesn't seem to require developers to adjust their apps for users to enjoy 90Hz or 120Hz.

That apparently isn't the case for one specific scenario on the new iPhone 13 Pro and iPhone 13 Pro Max. The 120Hz ProMotion display has definitely improved the scrolling experience, according to some users, but then things get janky in comparison to other parts of the UI. In particular, animations inside apps, like when menus appear and disappear, seem to still be running at 60Hz instead of 120Hz, resulting in some inconsistent experiences.

Am I correct in seeing that UIView.animateWithDuration APIs aren't clocked at 120Hz on iPhone 13? On UIScrollView, system ones, and Metal by the looks of it, rest is still 60Hz? pic.twitter.com/t3MeM9cj0E

— Christian Selig (@ChristianSelig) September 24, 2021

It turns out that this is exactly by design, and Apple wants developers to explicitly indicate that they want their apps to take advantage of all the refresh rates available on the iPhone 13 Pro and 13 Pro Max. This includes not only 120Hz but also other rates down to 10Hz. This, of course, requires updating their apps and submitting the updated app for approval, which might cause some stress for developers.

The reason for this requirement is that the higher ProMotion refresh rates naturally impact battery life, and Apple doesn't want to simply turn it on for all apps. It wants developers to give iOS the permission it needs to switch between refresh rates as it sees fit or let the developer decide the best experience it wants users to have, even if it means sticking to just 60Hz.