Nokia Lumia 920 successor codenamed 'Catwalk' to be thinner, lighter

Nokia Lumia 920 successor codenamed 'Catwalk' to be thinner, lighter. After a huge success of  Nokia Lumia 920 and 820.Both the devices are made up of Polycarbonate Plastics so,Nokia is planning to switch over from the polycarbonate plastic casing to an aluminium body , If this happens, then it could compete with the likes of Apple's iPhone.