As you know that in new iPhone 5 the height of screen is increased. That’s why if you are going to develop new App for iPhone 5 or want to update your existing Apps to become compatible with iPhone 5 then you must provide specific screen resolutions.
You must supply following additional screenshots with your new or existing Apps so that they are supported by new iPhone 5:
For Portrait: 640 x 1136
For Landscape: 1136 x 640
Please note that width of screen is not changed in iPhone 5 and is still 640.
If you want to edit your already uploaded App then you can go Manage Your Applications Section in iTunes Connect and then visit the Version Details Section for further procedure.
iTunes Connect –> Manage Your Applications –> Version Details
If you want to submit new iPhone App and you don’t supply new screen shots then your App will not be approved.
For full details please read this: