Are you releasing a flashlight app for the iPhone 4 or writing an application that use the capabilities of a certain device? Apple provides a UIKit Dictionary key called UIRequiredDeviceCapabilities for this purpose.
Apple define this key as: UIRequiredDeviceCapabilities (Array or Dictionary – iOS) lets iTunes and the App Store know which device-related features an application requires in order to run. iTunes and the mobile App Store use this list to prevent customers from installing applications on a device that does not support the listed capabilities.
More: UIKit Keys