Next iPhone prototype sighted at Foxconn

9to5Mac has source from inside of Foxconn that says the next iPhone prototype has surfaced. The source claimed that the next iPhone will retain the same shape, but screen size will be slightly bigger, believed to be 4-inch. It's said that the Retina Display has also been improved, though no screen resolution was mentioned. The back cover of the prototype is said to be made of metal, which seemed to suggest that Apple has exercise their ownership of LiquidMetal company. For your info, the original iPhone in 2007 has a metal back enclosure which was later changed to plastic in the 3G and 3GS models to improve radio performance.