A jury in US District court in San Diego has found Microsoft Corp. guilty of infringing on two patents held by Alcatel-Lucent and ordered it to pay $511.6 million in damages, marking the latest development in the 5-year-old feud between the two companies.

According to the ruling, Microsoft infringed on an Alcatel patent that includes the menu structure for selecting calendar dates included in Microsoft programs like the Outlook and Windows Mobile

The jury also awarded Alcatel-Lucent $10.4 million from Microsoft after finding the software maker infringed on a patent related to the use of a stylus on a tablet computer.

The jury also concluded that Dell infringed on a patent held by the French supplier and ordered Dell to pay $70,000 in damages.

Microsoft has said it plans to appeal against and is confident that the damages awarded against them will not be sustained on appeal.