iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple Calls for WWDC Developers, Launches iPhone SDK Beta 4
Meanwhile, Apple also quietly released the 4th beta of the iPhone SDK. Beta 4 adds at least one much requested feature: OpenGL ES support within the iPhone simulator. Previously, developers had to install directly to their iPhone to run OpenGL applications.
"The fourth beta version of the iPhone SDK includes Xcode IDE, iPhone simulator with Open GL ES support, Interface Builder, Instruments, frameworks and samples, compilers, and Shark analysis tool."Developers are continuing to work on iPhone/Touch apps and games to ready for the June launch of the iTunes App Store.