Microsoft could be shipping a preview release of the next major version of Windows—codenamed "Threshold" and expected to be named "Windows 9"—in either late September or early October, according to sources speaking to ZDNet's Mary Jo Foley. The preview will be widely available to anyone who wants to install it.

The final version of the operating system is currently believed to be scheduled for spring 2015.

Microsoft has all but confirmed some of the features that Threshold will ship with, including a new hybrid Start menu that includes bits of the old Windows 7 Start menu alongside new live tiles and the ability to run modern Metro applications in windows.

Other features that have been rumored include the removal of the Charms bar, with Metro apps having to embed their own search, share, and print buttons as appropriate. Windows 8.1 already took a step in this direction; although it has the Charms bar, with Windows 8.1, Metro applications started incorporating search buttons within their UI instead of relying on the search charm.

Virtual Desktop support has also been rumored, giving Windows for the first time ever a native capability to organize windows into multiple workspaces. There have also been claims that there will be some kind of Cortana integration.

Foley's sources told her that anyone using the preview will have to enable automatic updating, perhaps indicating that Microsoft intends to service and update Windows on a near-continuous basis in the future.