I have just had my iphone 4 for about a month, and still learning how things work. When using apps and you wish to close all apps being open, it was just a matter of double clicking the main button, and pressing the app which would put an x at the top of each open app, which you would just tap the x to close the app. I just received a message from apple, asking if I would like to update my iphone, which I have just done. The display is different, and now I dont know how to close the open apps to save battery, as the original way has changed to something else. Can someone give me an idea on how phone works now, or give me a reference on you tube I should watch to get to grips with the new way of doing things.