The U.S. Appeals Court for the Federal Circuit says Microsoft Corp. can keep selling its Word desktop software as it appeals an unfavorable patent ruling.

In May, a Texas district court said some versions of Microsoft's word processing software infringe on a Canadian technology company's patent. The dispute is over the way Word 2003 and Word 2007 let users customize document encoding.

The Texas judge had ordered Microsoft to pay Toronto-based i4i LLP $290 million and stop selling infringing versions of Word by the middle of October.

Redmond-based Microsoft has appealed the ruling and is set to present arguments on Sept. 23.