Apple has elected to pay $24.9 million to Dallas-based company Dynamic Advances to settle a four-year-old lawsuit relating to Siri. The company raised the suit in 2012, arguing that Apple's Siri assistant violated a patent owned by the Rensselaer Polytechnic Institute in New York, and licensed to Dynamic Advances. Apple's decision comes a month before the case was due to go to trial, and will see the tech giant pay $5 million at first to Dynamic Advances' parent company Marathon Patent Group once the case is dropped, before it follows up with the rest later.

The patent was the work of a Rensselaer Polytechnic Institute professor, and described a "natural language interface using constrained intermediate dictionary of results" when it was issued in 2007 — four years before Apple introduced Siri in 2011. Around half of the money given to Dynamic Advances' parent is expected to go to Rensselaer Polytechnic Institute, but the research university has yet to agree to a final figure with the company that gained the exclusive license to its patent.

As part of the settlement, Apple will be granted license continue to use Siri, and will be free of lawsuits based on the same patent for three years. The company has long been a target of patent holding companies — earlier this year, a US court ruled that Apple must pay $625.6 million to another firm for infringing on intellectual properties with a host of services, including FaceTime and iMessage. Apple has since filed for a mistrial.