Microsoft’s newest operating system, Windows 10, is now installed on at least 400 million devices around the world, the company said, as reported by GameSpot sister site ZDNet. The figure, which is up from 350 million at the end of June, is accurate as of September 26.

It counts the number of "active devices," so the figure may actually be even higher. An active device, according to Microsoft’s wording, is one that has been active in the past 28 days. The figure counts active devices across all Windows 10 devices, including PC, tablet, phone, Xbox One, and HoloLens.

At one time, Microsoft said Windows 10 was on the "fastest growth trajectory of any version of Windows ever." However, earlier this year, Microsoft said it was scaling back its goal to get Windows 10 running on one billion devices by 2018. That’s now not expected to happen until sometime later.

Windows executive Yusuf Mehdi mentioned recently that customer satisfaction around Windows 10 is "higher than any previous version of Windows."

However, it’s unclear how Microsoft measured satisfaction, and not everyone has been thrilled with Microsoft’s efforts to encourage them to upgrade to Windows 10. One woman sued the company over an unwanted upgrade and ended up receiving a $10,000 reward from Microsoft. That was of course an extreme circumstance and far from the norm, however.

The Xbox One is considered a Windows 10 device as of November 2015, as that’s when the New Xbox One Experience update introduced it as the console’s underlying OS.

Go to ZDNet to get the full story and all the context.

Microsoft offered Windows 10 as a free upgrade to select Windows 7 and Windows 8 users. This offered expired at the end of July.