The developer information, which has been around since August but only recently reported, suggests the iPhone 4S would be available in a black version and a white version. The current iPhone also comes in these two colors.
A revamped version of the iPhone 4 with the "S" branding would be similar to what Apple did in 2009 when, instead of launching a redesign of its phone with new featured, Apple simply repackaged its iPhone 3G with a speedier processor.
The iPhone 4 was a major upgrade from the iPhone 3GS both in design and in features. A faster processor, a front-facing camera, a completely redesigned package and the launch of a CDMA phone for Verizon Wireless were some of the things that separated the iPhone 3GS from the iPhone 4.
The iPhone 4S is expected to also contain a faster processor similar to what is currently found in the iPad 2, an upgraded camera and a few other changes.
Apple's next event is scheduled for October 4.