Microsoft is getting ready to unveil a new Lumia Windows Phone on September 4th. The invite comes just two weeks after Microsoft devices chief Stephen Elop showed off two new Lumia Windows Phones, and described one particular device as a selfie phone during a private internal company meeting. Microsoft’s invite appears to hint that the selfie phone, expected to be labelled Lumia 730, will be unveiled next month. Microsoft is also preparing to launch its Lumia 830, codenamed Tesla, with a PureView camera, and the company may well unveil both handsets during its event at the IFA consumer electronics show in Germany on September 4th.