Microsoft revealed today that Windows 10 is now in use on over 800 million PCs, a jump of about 100 million since last September.

“Thank you to all our customers and partners for helping us achieve 800 million Windows10 devices and the highest customer satisfaction in the history of Windows,” Microsoft corporate vice president Yusuf Mehdi tweeted today, linking to Microsoft’s By the Numbers website.

Microsoft hit the 700 million active devices milestone back in September, right around the time of its Ignite Conference, though we had reported on this one a bit early—OK, 5 months early—because the firm wasn’t accurately measuring the count until Terry Myerson left the firm. (Terry was measuring virtual instances of Windows 10 as “active devices,” which artificially inflated the number.)

Before that, Microsoft had announced the 600 million figure in November 2017. Presumably, that number was inflated by VM installs, however.

Assuming a steady rate of growth, Windows 10 should finally hit the long-anticipated 1 billion active devices milestone by this time next year. But perhaps it will happen a bit more quickly than that thanks to Windows 7 upgraders.