Also, when you see the Open button next to an app in the Update tab, that means it's already been updated. You are just being offered a quick way of opening the app, so you can check out the new features I suppose. When the app has yet to be updated it will have an Update button next to it. When it is in the process of updating it will have a blue circle with a square the middle. Progress is shown by the circle getting thicker in a clockwise direction. {I couldn't think of better way of describing it}