According to Russian analyst and Mobile Review editor Eldar Murtazin, 2 years old iPhone 3GS will stay on iOS 4.x.x and iOS 5 will not be brought to iPhone 3GS. The new iDevices which include iPad, iPad 2, iPhone 4 and iPod 4 will be included.
According to the Tweet of Eldar Murtazin:
Just one comment. Apple iPhone 3Gs wont be upgradable to iOS 5.x. iPhone 4 will.
Some time back 9to5mac reported that Apple is secretly testing iOS 5 for iPhone 3GS. No more words were said by Eldar.
Well according to me and I also expected that iOS 5 support will be removed from iPhone 3GS because iPhone 3GS on iOS 4.3.3 is a bit lagging while opening folders. So if iOS 5 comes out for iPhone 3GS it would be like iPhone 3G on iOS 4.2.1.
Any thing to say on it is very early and these things would be tell on time on 6th June 2011.