Although Apple has worked for two years to streamline iOS and macOS development by allowing iOS applications to run on Mac, the process has always been designed to be progressive, consisting of steps toward the ultimate goal. Today, Apple has unexpectedly taken one of its biggest steps with the launch of a “universal purchase” option for Mac applications developed with Xcode, allowing macOS and iOS applications to share an identification number single bundle that allows a platform transaction to register on both platforms.
Discovered by the developer Steve Troughton-Smith, the universal purchase option is “enabled by default for new Mac Catalyst applications created in Xcode 11.4”, released today with iOS 11.4, iPadOS 11.4, macOS 10.15.4 and tvOS 11.4 beta. “When you create a new Mac Catalyst application, it will use the same bundle identifier as your iOS application,” says Apple, assuming the developer specifies the iOS application information in the Xcode template wizard.
Catalyst is Apple’s cross-platform development framework, which was used internally by Apple under the code name Marzipan to develop certain proprietary applications for macOS 10.13 and iOS 12, and then presented to third-party developers for use in macOS 10.14. Developers can develop a single code base that works on iOS, iPadOS, macOS, and tvOS devices, and then create user interfaces optimized for small touch screens, large touch screens, or large non-touch screens with touch pads, mice, keyboards and / or remote controls.
The universal purchase feature seems to work only for newly created apps, although developers can work around this by simply republishing their previous Mac Catalyst apps using the iOS bundle ID. “If you choose to create your Mac Catalyst app with a custom bundle ID that doesn’t match your iOS app,” warns Apple, “you won’t be able to distribute the app as a universal purchase.”
Xcode 11.4 is now available for registered Apple developers through the corporate developer portal. In notes to developers published later, Apple says that universal purchases will begin in March 2020 and will also support the iPadOS and tvOS versions of the apps. A handful of categories in the Mac and iOS App Stores will be modified to reconcile differences between platforms, facilitate discovery – and potentially set the stage for a single App Store on multiple platforms.