Microsoft has sent business customers an invite to an event that promises a look at the next version of the Windows operating system, as well as future directions for the platform. The event is slated for Sept. 30 in San Francisco.

It’s expected that Windows 9, which Microsoft is developing under the code name “Threshold,” will employ a common kernel designed to run across all computing platforms—from smartphones and tablets to laptops and workstations.

Some details of the OS have already emerged. A video leaked by a German website indicates that Windows 9 includes several features that could make it easier to use than the current Windows 8.

The video, posted by German tech site WinFuture, shows that Windows 9 will once again have the Start menu, a popular feature that Microsoft removed from Windows 8 in favor of its Modern UI touch-centric interface. Many users complained that Modern UI, first introduced by Microsoft as the Metro interface, is too difficult to use on non-touch PCs that require navigation through a mouse and keyboard.

Windows 9, according to the video, also lets users boot straight to the classic Windows desktop, bypassing Modern UI if they wish. Microsoft has not confirmed the video’s authenticity. The operating system also lets users create and run multiple virtual desktops. It’s a feature that has been available on Apple’s Mac OS X and Linux machines.

The video further indicates Microsoft will add its Cortana personal assistant to Windows 9. Currently available only on Windows Phone, Cortana is similar in function to Apple’s Siri. Cortana can help users with a range of tasks—from finding a restaurant to travel directions.

Threshold, according to reports, will also contain features that automatically turn on or off depending on the host device. For example, a phone version would not provide access to Microsoft’s traditional desktop, while a SKU meant for PC users would bypass the Metro interface and boot straight to the desktop.

Windows 7 is currently Microsoft’s most widely used PC operating system, with a marketshare of 51.2 percent, according to NetMarketShare. Windows XP’s share checks in at 24.8 percent, while Windows 8/8.1 holds a share of 12.5 percent.