Mary Jo Foley has revealed that we will see the next version of Windows Phone either in January or February 2015.
The update, code-named Threshold, will combine Windows Phone and Windows RT.
Mary Jo writes:
There will be a separate preview of Threshold running on ARM processors, too. My sources are saying the current target date for that preview is January or February 2015. As the ARM-based version of Threshold — which should run on both Windows Phones and tablets — isn’t expected to include the Windows desktop, the focus will be on changes Microsoft is making to the Metro-Style Start screen environment.
At this point it is not clear what the UI of these new devices will be, but interactive Live Tiles have been strongly rumoured for the new OS, and Mary Jo’s sources have also said the OS will support side by side apps.
The January and February unveil for WP9 suggests we may see the OS at CES or Mobile World Congress 2015.
Microsoft is expected to show an early preview of the desktop version of the OS in late September or early October.