iPhone 6 already in testing, according to regular usage logs

The iPhone 6 smartphone running iOS 7 appears to be undergoing testing by Apple developers, with evidence of their existence leaking out ahead of launch.

According to developer sources speaking to TNW, product identifiers marking devices as "iPhone6,1" have begun showing up in usage logs in unnamed iOS applications. Given that Apple's current flagship handset, the iPhone 5, identifies itself to applications as the "iPhone5,1" or "iPhone5,2" depending on model, the entries would appear to indicate that the requests are coming from an as-yet unannounced device.

It's possible for a prankster with a jailbroken iPhone to fake such requests, of course, but TNW claims that its source has traced the requests back to IP addresses belonging to Apple's headquarters in Cupertino, California - suggesting that the requests are real.

What is not yet clear is exactly what device the requests originate from: having just recently launched a full smartphone product line refresh in the form of the iPhone 5, Apple is expected to go for an incremental update this year with a tweaked and updated iPhone 5S. The product number being reported by developers, however, points to an iPhone 6 - a full next-generation smartphone release which would bring rumoured improvements including a far larger screen, more powerful processor and support for near-field communications (NFC) radio technology.

Either way, the device is expected to include iOS 7, the latest release of Apple's mobile operating system. As well as launching on the next-generation iPhone, the software will roll out to older devices and Apple's tablet and media player products - and not before time: TUAW has reported of a glitch in the current iOS 6 software that prevented users' smartphones and tablets from leaving Do Not Disturb mode on New Year's Day this year.