Microsoft plans to end official support for Windows XP on April 8, more than 12 years after the operating system first became available to the public. Plenty of people are still using the OS, though. According to tracking firm Net Applications, Windows XP still runs on nearly 29% of the desktop systems browsing the web today. Perhaps due to the OS's persistent popularity, Microsoft has decided to extend anti-malware protection until July 14, 2015.
Windows XP will still be considered an unsupported OS after April 8. However, Microsoft will continue providing "updates to [its] antimalware signatures and engine" until the middle of next year. For consumers, the updates will come via Security Essentials. Enterprise customers will get updates to System Center Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection, and Windows Intune.
The additional 15 months of anti-malware updates are meant to give users more time to transition to a newer operating system. According to Net Applications' data, Windows XP's share of web traffic has dropped 10 percentage points in the past year, so people are clearly moving away from the OS. A substantial number of machines remain, of course, and it will be interesting to see how many of them persist after April 8—and after anti-malware support officially expires next year.
Unprotected PCs represent a risk to not only their own users, but also the Internet at large. Simply providing anti-malware updates doesn't guarantee the safety of an operating system, though. I've seen several infected machines that had at one time been running Security Essentials. As Microsoft notes in its blog post announcing the change, "the effectiveness of antimalware solutions on out-of-support operating systems is limited."