That means that the Windows Update system will download and start the upgrade process automatically on thousands of machines. At that point, you’ll still have a choice as to whether you upgrade or not. You can opt out of future notices to update as well.
“As we shared in late October on the Windows Blog, we are committed to making it easy for our Windows 7 and Windows 8.1 customers to upgrade to Windows 10,” a Microsoft spokesperson confirmed to The Verge. “We updated the upgrade experience today to help our customers, who previously reserved their upgrade, schedule a time for their upgrade to take place.”
The Windows 10 upgrade is free for Windows 7 and 8 users through July 29, 2016. After that, it’s anyone’s guess if or how much Microsoft will charge.