Apple has released the first beta version of iOS 9.3 to users participating in the developer program, the build arrives as 13E5181d and can be installed on any iPhone, iPad, or iPod touch compatible with iOS 9.
For a point release, iOS 9.3 looks to be fairly feature rich, with the inclusion of various new features and abilities including a night-time lighting mode called Night Shift (which sounds a lot like Flux), password and Touch ID protection with Notes app, and new abilities within Health app, News app, and CarPlay. Several new 3D Touch shortcuts are also added to the home screen of devices with iOS 9.3. Additionally, apparently limited to education users, there will be support for multi-users on single devices.
With a variety of new features and changes introduced to the beta of iOS 9.3, Apple has even created a iOS 9.3 preview page for all users, and a special Education Preview page for those who work with iOS devices in educational environments. Both are worth browsing through if you’re interested in what’s coming up for iOS.
Note the iOS 9.3 beta 1 release is aside from iOS 9.2.1 betas that are already out there.
Separately, Apple has also released first beta versions of WatchOS 2.2, tvOS 9.2, and OS X 10.11.4, though each of those updates are less feature rich than iOS 9.3, they appear to be required for compatibility purposes with iOS 9.3 devices.