As you can see, Apple is trying to avoid this so it’s now demanding that developers submit app icons in the new iOS 7 120-by-120 pixel resolution for the iPhone and 152-by-152 pixels for the iPad…
9to5Mac has Apple’s email communication to a developer, making it clear iPhone apps must include square icons in both 57-by-57 pixels and 120-by-120 pixels. Native iPad apps need app icons formatted for 72-by-72, 76-by-76 and 152-by-152 pixels.
“Apple does not explicitly mention iOS 7 in the email, but the resolutions match iOS 7′s requirements,†the publication wrote.
This compares to iOS 6 Retina requirements: 114-by-114 pixels for the iPhone and 144-by-144 pixels for the iPad. According to Manbolo, the corner radius of iOS 7 icons has been changed slightly to allow for a smoother appearance, see below.