Apple has begun allowing users on legacy versions of iOS to download the latest version of apps that are backwards compatible with their devices, as highlighted by a user on Reddit (via The Next Web). Specifically, when a user tries to download an app that is not compatible with his or her version of iOS from the App Store , Apple offers the user the option to download an older version of the app that is compatible with the device.
iOS 7 will be avaliable for free and will be compatible with the iPhone 4, iPhone 4S, iPhone 5, fifth-generation iPod touch, iPad 2, iPad with Retina Display (third- and fourth-generation), and the iPad mini, along with Apple's new iPhone 5c and iPhone 5s.
Article Link: Apple Begins Offering 'Last Compatible' Version of Apps for Users Running Legacy Versions of iOS