Exampleįor demonstration, I have created a new project with new Swift 5.5 features. Using swift -version will show a swift version that the terminal is using, but it not necessarily the version of swift that command-line tools see. You should get /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift which point to current active Xcode. You can find the toolchain path by running xcrun -find swift.

Apple Swift version 5.4 (swiftlang - 1205.0.

In my case, it is Swift 5.4 from Xcode 12.5. You would get the version that ships with your current active Xcode. You can check the currently selected toolchain like this. Most Xcode command-line tools use Swift toolchains based on the current active Xcode.

And that's what you are going to learn in this article. But if you also want to make it work with CI, you want to make your tools, e.g., Fastlane and xcodebuild know about the new toolchain too. If you want to prepare your app for new Swift's features, you can test it with your current Xcode version with the method in How to use a pre-release Swift version in Xcode. The new release of Xcode always ships with the latest stable version of Swift, e.g., Xcode 12.5 shipped with Swift 5.4, but since Swift is open-sourced, it doesn't need to wait for Xcode to release a new version. In this article, we will learn how to change the Swift toolchain for command-line tools. Selecting a Swift toolchain in Xcode will affect the Xcode IDE only.

In the end, we learn that changing the Swift version in Xcode doesn't affect any command-line tools. In the previous article, How to use a pre-release Swift version in Xcode, we learn how to use different Swift toolchain in Xcode.

Xcode version command line