SwiftUI and Catalyst: Apple executes its invisible transition strategy

The switch from the classic Mac OS to OS X was enabled by Apple creating something called Carbon, which was a set of tools that let apps written for the old Mac OS run natively on the new one. Classic Mac developers brought their apps over to OS X using Carbon, but it became clear over time that Cocoa was the future—and at one decisive moment, Apple went back on a previous promise and announced that there would never be 64-bit Carbon apps. But given that all Mac and iOS developers are already using Apple’s Xcode tools to develop their apps, I suspect that the pieces have been put in place for a fairly simple transition to a new processor architecture.

Source: www.macworld.com