A Microsoft spokesperson confirms the change via email:
Microsoft is updating the Support Lifecycle policy for Windows desktop operating systems, including Windows XP, Windows Vista and Windows 7.
The update will provide a more consistent and predictable experience for customers using Microsoft Windows operating systems across OEM, consumer and business editions.
Microsoft still requires that customers have the most current Service Pack installed in order to continue to receive updates.
Through this update, customers who remain on the most current supported service pack will be eligible to receive both Mainstream and Extended Support, for a total of 10 years.
Via Ed Bott: Microsoft quietly extends consumer support for Windows 7, Vista | ZDNet