Apple has released iOS 9.3 beta 4 to developers.
Apple first released beta 1 of 9.3 on January 12th to the surprise of everyone as 9.2.1 was still in beta.
Beta 2 was released on January 25th and Beta 3 was released on February 8th
iOS 9.3 brings some big new features including Night shift, password protection for the notes app, car play and education features, beta 3 added a new Wi-Fi Calling option for Verizon customers. Beta 2 added the Set Wallpaper option from the 3D Touch shortcut menu for the Settings app, introduced a new Add Playlist Songs to My Music switch in Settings → Music, added new 3D Touch shortcuts for the stock Tips app and refreshed the companion Watch app so that it shows your current watch face.
Other features and enhancements that will be enabled by iOS 9.3 include more personalized Apple News recommendations (along with faster performance, inline video and a landscape view on the iPhone), password or Touch ID protection for your notes in the Notes app, an all-new Activity section in the Health app, New/For You sections and a Nearby feature in CarPlay’s Music app and other refinements.