"You must install this update if you have been instructed to do so in a separate communication from Microsoft," the software giant said on its download site. The patches are available on Microsoft's OEM Partner and Download Centers.

Microsoft's patches come in the wake of a court order ordering to change the software or stop selling it. In December, the U.S. Court of Appeals for the Federal Circuit in Washington ruled against Microsoft's appeal of a patent-infringement verdict and gave the company a tight deadline to fix the issue.

The 449 Patent

At the heart of the issue is a Canadian company called i4i. The company claimed Microsoft violated its patents for custom XML in Word 2003 and Word 2007. In August, Texas U.S. District Court Judge Leonard Davis ordered Microsoft to pay in excess of $290 million and issued a permanent injunction against the software giant for what is known as the 449 patent.

The judge ruled that Microsoft willfully infringed on the patent and permanently enjoined Microsoft from selling Word 2003 and Word 2007 in the United States and using any infringing future Word products to open an XML file containing custom XML. The court also ruled that Microsoft can continue to offer technical support to current users of Word, but is not allowed to instruct new users on using the custom XML editor or to sell copies of Word with the disputed feature.

The injunction applies only to copies of Microsoft Word 2007 and Microsoft Office 2007 sold in the U.S. on or after the injunction date of Jan. 11, 2010. Products sold before this date are not affected.

Could Apple Be Next?

Last Friday, Microsoft asked the appeals court to hold an en banc review of its December decision. Kevin Kutz, director of public affairs at Microsoft, issued this statement: "The petition details significant conflicts we believe the Dec. 22 decision creates with established precedents governing trial procedure and the determination of damages, and we are concerned that the decision weakens judges' authority to apply appropriate safeguards in future patent trials."

Michael Cherry, an analyst at Directions on Microsoft, hasn't heard that the patch is an irritant to Word users. But he's not sure that's the issue. Even if people are using a Word product that has this feature, he said, they may not be using the XML feature. He calls it one of the most confusing issues he's ever seen. Confused, he said, by the magic pixie dust that is XML.

"What would a customer really have done with this feature, and did anybody even do it? We could be fighting over something that frankly is not only important to Microsoft but is also important to everybody. Is every company that wants to do this function going to get a license from i4i?" Cherry asked. "Microsoft has already removed the infringing technology. So the Microsoft story is kind of over. But could this potentially affect other products that Apple produces, or OpenOffice? Where is the line where this would crop up again?"