Preview at WWDC likely in June, followed by September launch.
Apple Seeds Sixth Beta of iOS 9.3 to Developers and Public Beta Testers
The sixth iOS 9.3 beta, build 13E5231a, is available as an over-the-air update and through the iOS section of the Apple Developer Center.
As a major update to the iOS 9 operating system, iOS 9.3 introduces several new features. There's a Night Shift mode to reduce the amount of blue light iOS users are exposed to in the evening by shifting the iPad or iPhone display to a warmer (yellower) color spectrum, and there are several features designed to improve the iPad for Education program, such as multi-user login. Multi-user login, while an appealing feature, is limited to MDM customers and is not available to the general public.
Multiple apps and features are also seeing updates in iOS 9.3. Apple News includes more personalized recommendations, faster updates, a landscape view on the iPhone, and support for in-line video, while Health includes an Apple Watch-style "Activity" view, Notes has an option to password protect individual entries, and third-party apps can add songs to Apple Music.
Apple Music for CarPlay offers "New" and "For You" sections for better music discovery in iOS 9.3, and a Nearby Feature in CarPlay Maps offers more information about points of interest that are close by. Paired with watchOS 2.2, an iPhone running iOS 9.3 is able to support multiple Apple Watches, and for iPhone 6s users, there are new Quick Actions for Weather, Settings, Compass, Health, App Store, and iTunes Store.
This is likely to be one of the last betas of iOS 9.3 we'll see before it is released to the public. Apple is planning to launch iOS 9.3 in the spring, perhaps following an event that is scheduled to take place on March 21.