Apple made it a mandate that browsers available in the iOS App Store must utilize the company’s open source WebKit, which has ruffled development company Nexendi’s feathers.

The company, which is a developer and business service supplier, has officially filed a lawsuit against Apple in French courts, which states it believes Apple should “sooner support the latest Web and HTML5 standards on its iOS platform.” The company argues that over the years, Apple’s WebKit has fallen behind other companies’ offerings when it comes to supporting HTML5.

As noted by Apple Insider, the mandate that all web browsers use Apple’s WebKit is at the heart of the problem. Alternative web rendering engines are not permitted within the iOS App Store, so while other browsers are available, they need to run WebKit.

“Not allowing the publication in Apple’s AppStore of web browsers that are not based on Apple’s own WebKit raises in our opinion the same issues as if Carrefour (a company similar to Walmart) was not selling any beans but those based on Carrefour’s seeds,” said Nexendi founder Jean-Paul Smets regarding the case law that the company is using. “This may be legal in other countries but in France, it is most likely not.”

Nexendi has already gone out of its way to suggest its user base abandon Safari on macOS and use an alternative. However, it can’t do the same thing for iOS, even if it wants to, because the company’s head says they’ve learned that “iPhones are the dominant devices with a loyal user base,” and abandoning the platform altogether is simply not an option.

The court hearing is scheduled for February 4, 2017.