At the Microsoft BUILD conference keynote today, CEO Steve Ballmer announced that the company has sold 4 million Windows 8 upgrades since the OSes launch on October 26, 2012. The upgrade is currently discounted to $15 for those who purchased a new Windows 7 PC recently, while others can digitally upgrade to Windows 8 Pro for a limited time for just $39.99.
Ballmer also mentioned business license for Windows 8 in his keynote, according to reporting by Ars Technica.
"We have sold tens of millions of units to our corporate customers, who can upgrade when they want to, but have no time pressure to do that any time soon," Ballmer said.
Microsoft did not provide any sales numbers for the Surface RT tablet that launched alongside the new operating system.