Unnamed "developers" contacted The Next Web claiming that traces of the next Apple smartphone and operating system have emerged in app usage logs.
One developer said that Apple has been testing hardware relating to a new 'iPhone6,1' identifier, relating to a device running iOS 7.
Released in September 2012, Apple's iPhone 5 previously bore the identifier 'iPhone5,1' and 'iPhone5,2' for the LTE model of the handset supporting 4G.
The Next Web investigated the developer's claims and found that the app requests came from an IP address at Apple's headquarters in Cupertino, California.
Device and OS data can be faked, but the site believes that the legitimate IP footprint suggests that Apple is indeed testing the new model of the iPhone.
It is thought that Apple started working on iOS 7 last year, and if the firm follows previous release patterns, the software will be launched at the WWDC event in the summer.
The next model of the iPhone is expected to follow in the autumn as Apple continues its annual upgrade cycle for the hugely-popular device.