Apple just releases Xcode 6.3 Beta with Swift 1.2 update.
Xcode 6.3 requires a Mac running OS X 10.10.
Xcode 6.3 includes SDKs for iOS 8.3 and OS X versions 10.9 and 10.10. To develop apps targeting prior versions of OS X or iOS, see the section "About SDKs and the iOS Simulator" in What's New in Xcode available on developer.apple.com or from the Help > What's New in Xcode command when running Xcode.
This release is a single application bundle. To install, double-click the downloaded DMG file, and drag the Xcode-Beta.app file to your Applications folder.
From within Xcode, you launch additional developer tools, such as Instruments and FileMerge, via the Xcode > Open Developer Tool command. You can keep the additional tools in the Dock for direct access when Xcode is not running.
Installing Xcode on OS X Server
To use Xcode's Continuous Integration service with this Xcode beta, you need OS X 10.10 with OS X Server 4.0.
Once you have installed OS X, OS X Server and Xcode, point OS X Server to this Xcode beta:
1. Open Server.app
2. Select the Xcode service
3. Choose Xcode