In iOS 6, icon's borders are cropped, making them 114x114 on each side. However, in iOS 7, the entire 120x120 icon is used. The Pocket Edition icon has a gradient around the edges that is barely noticeable on the iOS 6 icons, but becomes very heavy when viewed in iOS 7. As all other operating systems use the iOS 6 icon's design, I suggest that icon is scaled up, making it match the others.

(In Picture)
Left: iOS 6 and Android
Right: iOS 7