Microsoft’s Windows 10 operating system is now being used by more than 270 million people. Windows boss Terry Myerson revealed the metric earlier today during the keynote for Microsoft’s annual Build developer conference in San Francisco.

As Computer World highlights, the figure was expressed in a software-as-a-service style. What that means is Microsoft isn’t measuring total device installations or daily activity, but how many people ran Windows 10 at least once over the past 30 days. What’s more, the figure isn’t exclusive to Windows 10 PCs as it includes smartphones, tablets and Xbox One consoles that are running the new OS.

Elsewhere, Microsoft said that the next major update to Windows (known up to this point by its codename, Redstone) will arrive this summer.

Dubbed the Windows 10 Anniversary Update, it’ll deliver a number of new features and improvements including Windows Hello authentication support for apps and websites, Windows Ink, the arrival of Universal Windows Platform apps on the Xbox One, proactive Cortana suggestions, the ability to access Cortana from the lock screen, background music on Xbox One, Xbox features on PCs and much more.

The update will also add the Linux command line to Windows 10, something the crowd of developers overwhelmingly approved of.

Project Centennial is another milestone Microsoft talked about at this year's Build keynote. The Desktop App Converter helps developers bring Win32 and .NET applications to the Windows Store, effectively turning them into UWP "Modern" apps. As you might recall, Microsoft pushing for UWP spurred some controvery recently when Epic Games founder, Tim Sweeney raised concerns about a Windows "walled garden".

The Windows 10 Anniversary Update will be free for everyone, Microsoft said.

Microsoft’s Build conference runs through April 1.