The new version of Xcode is available for download. Xcode 9.0 includes Swift 4 and SDKs for iOS 11, watchOS 4, tvOS 11 and macOS High Sierra 10.13.

• The source code editor has been completely rebuilt for amazing speed. It scrolls at a constantly smooth rate, no matter the files size, also supports Markdown.
• Refactoring to easily select and modify structure of code
• Swift 4 compiler can also compile Swift 3 to aid transition
• Xcode 9 makes working with source control – and with GitHub – easier and more tightly integrated.
• Simulator app updated.