iphone5 screen size

Hopefully iphone will hide things off the stage, but if not you could add a black sprite or movieclip to cover things that are not on the stage and then either have a listener to tell when objects are added so you can swap depths, or add every new object to already existing containers that has lower depths than the "cover object". The best is of course to resize the background, and position things based on the stage width and height.

Can be positive, maybe Apple will mask that area, but I suspect not. I used to do apps so that the stage size was iPhone ratio, and I had extra content above and below the stage that gets revealed on iPad. Later I changed to having an iPad size stage, and having extra content left and right of the stage (this is for landscape I'm describing). That was great and would work for even the widest Android, and for the new iPhone 5. These days I have a stage size that is about 14:9, and on iPad you see the full height and most of the width, and on the new iPhone you would see the full width and most of the height. It works extremely well.