Apple has responded to speculation that it is limiting third-party developer access to ProMotion technology, saying all apps can access the feature through a plist entry. The company has also identified a Core Animation bug that could be contributing to the issue.
On Friday, developers reported apparent issues in iOS 15 that seemingly cap animations on iPhone 13 Pro at 60Hz. The handset is the first iPhone to implement ProMotion technology, which enables dynamically variable refresh rates of up to 120Hz.
Apple confirmed to AppleInsider that all developers can take advantage of ProMotion’s range of refresh rates on iPhone 13 Pro, but there is a caveat.
The company notes iOS will ramp refresh rates for standard user interface animations automatically without developer intervention, though app makers looking for full access to ProMotion will need to add a plist entry to declare that their wares utilize available higher rates. Declaring support helps save iPhone battery life by allowing iPhone to make a determination about which apps are provided high refresh rate options.
In practice, the requirement means certain actions, like scrolling, will be rendered at 120Hz, while others are not. Developers like Apollo creator Christian Selig are seeing the discrepancy in their apps with non-standard animations such as pop-up handling, which are limited to the 60Hz cap. This behavior should change once app plist entries are updated.
More information about the required plist entry will be made available to developers in the near future.
Apple has also identified an issue with animations built with Core Animations and said a fix is coming in a future software update. Until then, animations that rely on Apple’s framework might be stuck at 60Hz.
ProMotion is a variable refresh rate technology that intelligently chooses an optimal rate depending on onscreen content and user interaction. Fast-moving graphics and scrolling operations are afforded higher rates, while static content is displayed in rates as low as 10 updates per second to save battery life.