Reports from China say that Apple will release two new iPhones this year. The first will be an upgraded version of the current model and is expected to be called the iPhone 5S, while the second is described -according to translated reports - as the iPhone Math.

The name seems unlikely given Apple's naming history for the iPhone. The handset is said to feature a larger screen than the iPhone 5 - 4.8-inches, compared with the current model's 4.6-inch screen.

The China Times says the two iPhone models will go into production in April, before a release in the summer.