The Supreme Court has agreed to hear the ongoing patent dispute between i4i and Microsoft, it said this week.

A trial date has not been set, however.

In 2009, a court ruled that Microsoft's use of XML violated an i4i patent. In Dec. 2009, Microsoft agreed to alter the design of Word, although the company continued to appeals process. Microsoft also agreed to pay $290 million in damages.

In March 2010, an appeals court upheld the i4i decision. Microsoft then applied for an en banc appeal of the entire appellate court, but was denied. In July, the U.S. Patent and Trademark Office re-examined the i4i patent in question, confirming its legitimacy.

Last Wednesday, the U.S. PTO denied Microsoft's second ex parte application for a re-examination of i4i's patent, United States Patent No. 5,787,449 ('449), the subject of i4i v Microsoft, i4i claimed.

"The PTO has again affirmed the validity of our patent by denying Microsoft's request for a second reexamination," i4i's chairman, Loudon Owen, said in a statement.

The Supreme Court's agreement to hear the case, however, means that Microsoft's appeal is still alive. Owen said if the high court overturns the previous rulings, it could spell disaster for other software innovators.

"The attack on patent holders and the adverse implications from the standard Microsoft is proposing is unprecedented and would deal a devastating blow to any US patent holder, large or small," Owen said. "Naturally, the proposed standard would be particularly destructive to the value of patents for inventors, technology pioneers and entrepreneurial companies that don't have the resources of Microsoft and other giants."

Microsoft representatives weren't immediately available for comment.