Users of the recently released iOS 10.3 beta who open a 32-bit app are seeing a message warning them that the app "will not work with future versions of iOS" and must be updated to continue working.
The somewhat vague message, flagged on Twitter by Peter Steinberger, founder and CEO of PSPDFkit, is being taken to mean that Apple may only support 64-bit apps in iOS 11. If so, the move could complete a three-year effort to move developers off 32-bit apps in the App Store.
In recent years Apple has phased out iOS support for older devices with 32-bit chips, such as iPhones and iPads in the A5 and A6 families.
As noted by Ars Technica, the list of devices currently supported by iOS 10 could lend itself to dropping support for 32-bit apps completely. Apple has encouraged developers to build 64-bit apps since releasing the iPhone 5s in 2013, which featured the 64-bit A7 chip and iOS 7, the first 64-bit version of iOS.
Every device Apple has released since this pair has a 64-bit processor, and beginning in 2015 Apple mandated that new apps and app updates support 64-bit, which offers better app and CPU performance on mobile devices. These devices include all iOS device models newer than the iPhone 5s, iPad Air, and iPad mini 2.
The cheaper iPhone 5c, released at the same time as the 5s, had the 32-bit A6. The iPhone 5c, iPhone 5, and iPad 4 remain the only 32-bit chip devices supported by iOS 10. If they don't make the cut to iOS 11, it could allow Apple to drop all 32-bit code in iOS.
Nudging developers to 64-bit comes alongside Apple's recent efforts to remove outdated and broken apps from App Store. Apple began contacting developers last September requesting the apps be updated and vowed to remove them immediately if they crashed on launch. By November Apple had purged nearly 50,000 apps, according to TechCrunch.