Microsoft Extends Windows 8.1 Update Migration Deadline
 

Microsoft has extended the migration deadline for business users of Windows 8.1 for an additional three months. End using consumers however, are still warned to make the move within the next month. If users of Windows 8.1 do not upgrade to Win8.1U within the limited time frame, they will not receive further security fixes.

http://www.hardocp.com/news/2014/04/...on_dead line/