Nokia is planning to unveil two new Windows Phone 8 devices at a joint event with Microsoft on September 5th. Sources familiar with the two companies' plans have revealed that Nokia is working on an "Arrow" Windows Phone 8 device that is set to be announced alongside a "Phi" handset. Both the devices are said to be part of Nokia's Lumia range, with the Arrow and Phi codenames serving as temporary monikers.

AT&T will stock Nokia's Phi handset initially as an exclusive hero device, expected to feature a large curved glass display as the successor to the Lumia 800 and 900 range, complete with the typical polycarbonate body. The Arrow Windows Phone 8 handset is said to be a mid-range one that will be available on AT&T and T-Mobile in the US. An almost identical variant, codenamed Atlas, will also be available on the Verizon network — but its announcement is likely to come later. A prototype device and parts for Nokia's Windows Phone 8 devices have leaked to the internet in recent weeks, but Microsoft and Nokia will unveil the final design of both handsets next month.