iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple Releases Beta 3.1 iPhone Firmware and SDK to Developers
Even with the recent release of iPhone 3.0, Apple is hard at work at the next update: iPhone 3.1. Apple seeded registered developers with a beta version of the firmware and SDK today. Few details were provided as to the improvements to be found in the new firmware. The latest build number is 7C97D.