iOS 13: More system apps and components written in Swift

Apple released the new Swift programming language at WWDC in 2014. Swift is the future programming language for Apple platforms. Since then, many third-party developers have begun to use Swift to write programs, but Apple's iOS and macOS systems, as well as various system applications, are still written in Objective-C.

There are many reasons for this. First, a lot of Apple's current Objective-C code works perfectly. There is no need to rewrite it for the sake of rewriting it. Don't create new problems if there are no problems. Second, until Swift 5.0, the ABI was not stable. Swift 5.1, modules were stable, which is important for large-scale deployment at the system level.

Developer Alexandre Colucci has been counting the use of Swift in Apple systems since iOS 9. The latest data shows that in iOS 13, there are a total of 141 binary executable files written in Swift, more than twice that of iOS 12, which had 66.

In iOS 13, new features and applications such as Sidecar, Find My, and Reminders are all written in Swift. Other apps that use Swift include Health, Books, and some system services, services responsible for pairing AirPods and HomePod, and the offline search function of the Find My App.