The US Patent and Trademark Office has confirmed the validity of an i4i patent that was disputed by Microsoft.
The patent, number 5,787,449, relates to the Custom XML technology used in previous versions of Word. It builds on XML to improve the way in which data can be structured.
It's "a critical technological bridge to controlling and managing this sprawling octopus of data and converting it into useful information," according to Loudon Owen, Chairman of i4i.
After a verdict last December, Microsoft was ordered to pay $290 million to i4i and remove the offending technology from its products. It did so - and it's not going to be in Office 2020 - but the company fought on.
"This is a very material step in our litigation against Microsoft. Put simply: i4i's patent is clearly and unequivocally valid," said Owen.
"Even though Microsoft attacked i4i's patent claims with its full arsenal, the Patent Office agreed with i4i and confirmed the validity of our '449 patent."
But the saga may not be over even yet - Microsoft still has the option of appealing to the Supreme Court.