updated 05:10 pm EDT, Tue May 24, 2011
May be consistent with patterns of obsolescence
iOS 5 won't run on 2009's iPhone 3GS, claims analyst and Mobile Review editor Eldar Murtazin. "Just one comment. Apple iPhone 3Gs wont be upgradable to iOS 5.x. iPhone 4 will," he explains in a Twitter post. While there are no more statements to support the rumor, Murtazin has in the past obtained unexpectedly accurate information, such as early knowledge of the Nokia N8. Since a preview is anticipated at WWDC in early June, iOS 5 could be far enough into development for specifications to leak.
Apple has reportedly been testing iOS 5 on the 3GS and third-generation iPod touch. The company may have decided that iOS 5 doesn't run fast or well enough on 2009 devices though, and a two-year gap is roughly consistent with Apple's recent patterns of planned obsolescence. Support for the original iPhone was dropped with iOS 4 in summer 2010, and the iPhone 3G and second-gen Touch were abandoned when iOS 4.3 was released earlier this year.
iOS 5 may also be especially resource-intensive. The firmware is expected to be a major revision, potentially changing fundamentally in character to support things like cloud streaming. Another target area is thought to be push notifications.