The decision was announced this week on the company's Anti-Malware Protection Center website. Despite the decision to keep anti-virus support alive, the company emphasized XP will still cease to be supported. The means users will not receive new security updates, non-security hotfixes, free or paid assisted support options, or online technical content updates from Microsoft.

Some press reports about this issue say estimates are
that 20 to 30 percent of Microsoft system users are still running XP. It is generally assumed that the use of XP remains strongest with small business, including small accounting firms.

The blog post on the center said that for enterprise customers, the continuation of anti-malware supports applies to System Center Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection and Windows Intune running on Windows XP. For consumers, it applies to Microsoft Security Essentials.

However, the company warned that "Our research shows that the effectiveness of antimalware solutions on out-of-support operating systems is limited."