Microsoft has changed its mind over killing Windows XP entirely this April and announced it will continue providing updates to its security products (antimalware engine and signatures) until middle of July, 2015. Thus, XP will get another year’s life. Back in 2013, Microsoft said it would halt all updates on the same day as the end of support date for Windows XP this spring.
In other words, Microsoft Security Essentials will still get updates after full support ends for operating system. The same will go for System Centre Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection, and Windows Intune used on XP. But it should be noted that Microsoft will still end full technical assistance for Windows XP this spring and you won’t be able to download Microsoft Security Essentials on Windows XP since that date.