A ban on Microsoft selling certain versions of its flagship products Word and Office has begun.
The software firm was made to change elements of the software by US courts after a patent dispute with Canadian firm i4i. Microsoft said that it had complied with the court's ruling and would now offer "revised software" in the US. The court ruling means that Microsoft must also pay i4i damages of $290m (£182m).
However, the firm said on 8 January that it had filed another appeal against the injunction.
They have complied and are issuing patches to update the applicable software. However, they are within their rights to appeal this decision. If this reaches the Supreme Court then it may be possible to redefine some of the legal precedents in terms of software patents within the US legal system. There is more at stake here than MS simply rolling over and capitulating.