iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple Releases iOS 6 Golden Master to Developers
Apple has seeded the Golden Master (GM) version of iOS 6 to developers today. The GM release represents the final version that will be shipped to customers. Apple will be releasing iOS 6 to customers as a free download on September 19th.
Apple has provided an extensive preview of what's new in iOS 6. This includes Maps with turn-by-turn directions, enhancements to Siri, a new Passbook app, Safari improvements and more.
iOS 6 will be available for the iPhone 4S, 4, 3GS, new iPad, iPad 2 and 4th generation iPod Touch.