iOS 6 is the last supported iOS for the 3GS. I have a 3GS with iOS 6 on it. It is slow and sluggish when flicking through home screen icons and even more so when opening apps. IOS 8 is most likely the last iOS the 4S will support. If I upgrade my 4S from iOS 7 to iOS 8, will I have the same problems on the 4S as I do on the 3GS? Thank you.