It looks like Apple began app-compatibility testing for its next-generation mobile operating system, the iOS 7. Various app developers have been logging requests from devices bearing the system ID "iPhone6,1" hinting at the new OS build. For reference the iOS 6 that powers iPhone 5 gets logged as either "iPhone5,1" or "iPhone5,2" with the latter indicating an active 4G LTE network available with the device (helps Apple build stats).
OS and browser identifications can be easily faked, and to rule that out, developers found the IP addresses from which these "iPhone6,1" labeled requests originated, to trace back to Apple headquarters, in Cupertino, California. No other details about the operating system could be derived from the logs. In all likelihood, the new OS could make it to current, and upcoming Apple devices later this year.