According to a post on Apple's developer website, all developers will be required to submit apps that are compatible with iOS 7 and built with Xcode 5 as of February 1, 2014.Until now, the App Store has been accepting the submission of both apps that were built from the ground up for iOS 7 as well as those that were built for iOS 6 using older versions of the company's developer toolset. This was done primarily as a temporary measure, so that companies with existing apps wouldn't have to choose between abandoning their users who chose not to upgrade to the latest version of Apple's operating system or supporting both iOS 6 and 7 in a single executable--which, given the user interface differences between the two versions of iOS, would be a pretty significant challenge.Instead, Apple built much of the "old" iOS 6 UI into iOS 7, allowing developers to take advantage of it if they so chose. As developer liaison David Duncan
