Are you using Windows 10?

Microsoft said more than half a billion devices are powered by its latest software, called Windows 10, to power their PCs, tablets and phones.

"The opportunity for us as developers to have impact on all parts of society and all parts of economy has never been greater," said Microsoft CEO Satya Nadella. He was speaking at the company's Build developer conference in Seattle Wednesday.

The milestone comes nearly two years after Windows 10's release, which was offered for free to people using any version of Windows going back to 2009. Microsoft designed it in part to respond to criticisms of its Windows 8 PC software, which was panned for its "steep learning curve" when it was released in 2012.

Windows 10, by comparison, was called "vastly improved," when released in 2015.

Microsoft initially said it expected a billion machines would be powered by Windows 10 by 2018, but has since said it will likely miss that deadline.