Apple announced today the release of the iPhone 4GS.

Some of the major improvements, from an app developer point of view:

• The new A5 chip will give mobile developers new opportunities for complex calculations. More than just the gaming examples Apple demonstrated in the keynote, productivity and business applications can also reap large benefits from the new chip.
• The new camera and photography software will place an increased focus on video and photography applications. We see photography and videography apps as a major growth area on iOS.
• Although Siri is still in beta, at the moment we are not aware of any opportunities for third-party developers to integrate with Siri and allow voice control of their applications.
• AirPlay Mirroring, introduced on the iPad 2, makes it easier to display iOS apps in presentations.

The iPhone 4S is largely an incremental improvement over its predecessor rather than a complete redesign. It has many new and exciting features, but at this point it does not represent as large of a shift in iOS app development as iOS 5.