Swiftify does not include a converter between different Swift versions because such a converter exists in Xcode.
To migrate to a newer version from Xcode, choose Edit -> Convert -> To Current Swift Syntax from the Xcode menu.
Depending on your source code's Swift version, you might need a different Xcode version for the conversion. To get an earlier version of Xcode, you can use your Apple Developer Account to download it from the Apple Developer Portal:
- Swift 1 -> 2, Xcode 7
- Swift 2 -> 3, Xcode 8
- Swift 3 -> 4, Xcode 9
- Swift 3 or 4 -> 4.2, Xcode 10
- Swift 4 or 4.2 -> 5, Xcode 10.2.1
- Swift 4 or 4.2 -> 5.1, Xcode 11.1
- Swift 4 or 4.2 -> 5.2, Xcode 11.4
- Swift 4 or 4.2 -> 5.3, Xcode 12
- Swift 4 or 4.2 -> 5.4, Xcode 12.5
- Swift 4 or 4.2 -> 5.5, Xcode 13
For more information on migrating to Swift 5, check Swift’s official blog where you can also find migration guides for earlier versions of Swift.
Note: Xcode 13 converts your Swift code to Swift 5.5, even though in the Swift Language Version dropdown under Build Settings, it shows Swift 5 (learn more).
Since Swift 5.0 achieved ABI Stability, all new changes to the language are additive in nature. As there are no changes to the existing format, there isn't a syntax converter for converting between Swift 5.x versions in Xcode.