The invite reads,
Microsoft Devices Group will be at IFA (Berlin) this year on September 4, 2014.
So, that confirms “PureView” camera of Lumia 830 and Orange theme rhymes with the leaked Lumia 730 render from China. It also talks about “Join us for More Face Time”. So, there is your hint about the 5 MP Selfie camera of Lumia 730. You may be aware that earlier Nokia used to make a “Color”, color of the season and this time the honor goes to Orange.
So, Berlin it is, 4th September at IFA!! Mark your calendars.