The iOS App Store has been silently updated on Apple’s end to allow users running older versions of iOS to install legacy versions of apps that are no longer supported by their software. In the screenshot above, for example, an iPhone 5 running iOS 6.0.2 is prompted to install the “last compatible version” of Weatherbug, which normally requires iOS 6.1. Choosing to download the last compatible version grabs the most recent version of the app that supported 6.0.2 and installs it on the device.
This is especially good news for users on old hardware, such as the iPhone 3G or original iPhone, which don’t support anything beyond iOS 3.1.3. Users of those apps will now be able to run apps that they ordinarily would have been unable to install due to their outdated OS. Also benefiting from this change are iPhone 3GS owners who cannot upgrade to iOS 7, or users of newer devices who choose not to update to Apple’s latest OS.