iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Mac OS X 10.6.2 Build 10C519f Seeded to Developers
Apple reportedly notes approximately a dozen areas of change addressed in the new build, on top of the nearly four dozen changes included in the previous build. Apple also lists nearly 150 specific focus areas upon which developers are asked to place their testing efforts. As for outstanding known issues yet to be addressed, Apple apparently addresses four such items, including issues with video corruption, Core Data output, and System Preferences hanging.