Both Microsoft and Apple tried to plug the holes in their ecosystem with cross-platform apps – in Microsoft’s case UWP apps which would bring desktop apps to the phone, and in Apple’s case Catalyst apps, which would bring iPad apps to the moribund MacOS desktop App Store.
Microsoft’s solution was however somewhat more feature-rich than Apple’s first offering, but Apple has finally plugged a major hole by allowing developers to sell the iPad and macOS versions of an app as a single bundle available on both platforms, much like UWP apps worked on Windows Phone and PC.
The Universal Purchase feature was released as part of Xcode 11.4 and requires developers to specify the same bundle identifier as their iOS app in the Xcode template assistant when creating a new project or when updating an existing project in the Project Editor.
Universal purchase will be enabled by default for new Mac Catalyst apps created in Xcode 11.4, meaning that when you create a new Mac Catalyst app, it will automatically use the same bundle identifier as your iOS app.
In fact, the feature can work for any Mac app with via the bundle identifier, meaning developers can now bundle any desktop and iOS, iPadOS, watchOS and tvOS app in a single purchase easily.
Developers can read more at Apple here.