The release of Apple's newest operating system for the iPhone, iPad, and Touch devices was introduced with 1500 new APIs for developers to explore. When expanding the platform, Apple identified "tent poles" of functionality necessary to support a richer app experience. The iPhone SDK 4 arrives with seven new tent pole features for users and services for developers. Much like the release of OS 3, Apple has maintained compatibility of the new OS to all Touch platforms while limiting some of the new functionality to Gen 3 hardware.
Developers receive the new iPhone OS 4 with all the APIs necessary to take their 185,000+ apps to the next level.