Microsoft Malware Protection Center :
Microsoft has announced the Windows XP end of support date of April 8, 2014. After this date, Windows XP will no longer be a supported operating system. To help organizations complete their migrations, Microsoft will continue to provide updates to our antimalware signatures and engine for Windows XP users through July 14, 2015.
This does not affect the end-of-support date of Windows XP, or the supportability of Windows XP for other Microsoft products, which deliver and apply those signatures.
For enterprise customers, this applies to System Center Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection and Windows Intune running on Windows XP. For consumers, this applies to Microsoft Security Essentials.
Our research shows that the effectiveness of antimalware solutions on out-of-support operating systems is limited. Running a well-protected solution starts with using modern software and hardware designed to help protect against today’s threat landscape.
Continue at source:
http://blogs.technet.com/b/mmpc/archive/2014/01/15/microsoft-antimalware-support-for-windows-xp.aspx