The eight-year-old (so far) legal battle between Apple and VirnetX has taken a new turn after a Texas federal court ordered the iPhone maker to pay $502.6 million to the company. Bloomberg reports that a grand jury found Apple guilty of infringing on patents related to secure communications.

While VirnetX does create some products such as a “secure mail and messaging system called the Gabriel Collaboration Suite,” their business model mostly involves filing patents in the hope of getting large companies to license its technology, or, more often, suing them in patent infringement lawsuits. The company is what's known within the industry as a ‘patent troll.’

VirnetX has been gunning for Apple since 2010 when it filed three lawsuits alleging that its FaceTime, VPN on Demand and iMessage features infringed on owned patents. Since that time, there have been numerous trials and appeals.

Apple was ordered to pay VirnetX $625.6 million in early 2016—the result of two of the lawsuits begin combined. But a judge invalidated the ruling a few months later. He said combining the two cases created the "potential for juror confusion,” and ordered two new trials to deal with the claims individually.

In October 2017, Apple was ordered to pay VirnetX $440 million, which it appealed. The latest ruling has seen VirnetX’s stock rise as much as 44 percent, though it had little effect on Apple’s share price. Kendall Larsen, CEO of VirnetX, said the damages were "fair,” but the decision might not stand. The Patent Trial and Appeal Board ruled the patents invalid in 2016. “The Federal Circuit, which handles all patent appeals, declined to put this trial on hold, saying it was so far along that a verdict would come before a final validity decision,” writes Bloomberg.

Back in 2010, Microsoft agreed to pay $200 million to VirnetX to settle a patent dispute. Later, the Redmond firm paid another $23 million for updated products.