As part of iOS 7′s dramatic UI changes, app icons have been slightly enlarged and with iOS 7 release being just around the corner ( presumably Sept 10th, or later the same week ), Apple has started asking developers to submit larger app icons that are optimized for iOS 7.
The non-iOS 7-optimized app icons have a small white border around it, as shown in the screenshot above ( Netflix icon vs iOS stock icons ). In order to avoid this interface issue, developers will need to include larger icons in their applications. iOS 6 icons on the iPhone come in at 114 x 114 pixel resolutions, while iOS 7 icons are slightly larger at 120 x 120 pixel resolutions. For the iPad, iOS 6 icons are at resolutions of 144 x 144, and on iOS 7 they come in at a resolution of 152 x 152
To learn more about iOS 7 UI and icons, check out this article.