The next-generation iPhone will ship in the fall, like the iPhone 4S, claims a "close source" for the Boy Genius Report. The 4S was the first iPhone to skip Apple's previous June/July launch schedule, and if the new claim is accurate it suggests that Apple may be shifting its timetable permanently. The source also notably mentions that the new phone should incorporate a rubber or plastic material similar to that used in its iPhone 4 bumpers.
