The update follows Lumia Amber, Lumia Black and Lumia Cyan, and according to their sources Windows Phone 8.1 GDR 1 will be called Lumia Denim.
The update is said to be ready to announce at IFA today, and will be rolling out to the Nokia Lumia 930/1520/Lumia Icon and also the Lumia 830 very soon after.
Other, presumably less powerful handsets will have to wait till Q4 2014 for the software, who’s exact features have yet to be revealed, but will of course include the GDR1 feature such as Folders that many of us are already using.
The rumour of course competes with a recent leaked screen shot which showed the next version of Windows Phone 8.1 will be called Lumia Debian Red. That name is however not exactly Microsoft, so we would not be surprised to see it changed to something more true blue.