Apple has seeded the latest beta of iOS 8.3 to its public beta testers. The new build is also available over-the-air to developers as build 12F61. The build is also available for download via the iOS Developer Center.

Also available is a new Xcode 6.3 beta (build 6D554n), which includes support for Swift 1.2. A new beta 3 seed for the third-generation Apple TV is also available.
The final version of iOS 8.3 is expected to being improvements to Siri, including new languages, more diverse emoji, and a number of bug fixes.