iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
iPhone OS 4.0 Claimed to Include Multitasking, Revamped Interface
- There will be multi-touch gestures OS-wide. (Would make sense for that as the rumored OS for the iTablet is close if not the same as the iPhone)
- "A few new ways" to run applications in the background -- multitasking.
- Many graphical and UI changes to make navigating through the OS easier and more efficient. We haven't had this broken down, but we can only hope for improved notifications, a refreshed homescreen, etc.
- The update will supposedly be available for only the iPhone 3G and 3GS, but will "put them ahead in the smartphone market because it will make them more like full-fledged computers" more than any other phone to date. Everyone is "really excited."
- The last piece of information is the most vague, but apparently there will be some brand new syncing ability for the contacts and calendar applications.