Exactly a week ago, in Securing Windows XP after the Deadline Just Got Harder, I wrote about Microsoft's decision to end support for Microsoft Security Essentials on Windows XP at the same time support for the OS ends (April 8, 2014). Just today, Microsoft has decided to extend support for Security Essentials updates and antimalware signatures for over a year past the April 8 deadline for Windows XP support.
In the statement, Microsoft has announced that those continuing to run Windows XP after its end-of-life can expect to continue receiving Security Essentials updates until July 14, 2015.
In addition to the consumer version of Microsoft's antimalware product, Enterprise customers can also expect continued security coverage for Windows XP. System Center Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection, and Windows Intune customers can also continue to manage AV security for those workstations still running Windows XP.
This is in no way a reprieve for Windows XP, only a stop-gap measure to help secure old PCs while companies continue migrating to a more modern operating system.
Microsoft blog: Microsoft antimalware support for Windows XP