The war of words between Apple and Imagination Technologies seems to be escalating. A few days after Imagination’s annual report accused Apple of making ‘unsubstantiated allegations,’ the Cupertino company has hit back.

Apple says that the chip designer’s response has been ‘inaccurate and misleading,’ and presents a very different timeline of events …

While Imagination disclosed in April a warning from Apple that it would cease to be a customer within two years, Apple told Bloomberg that it first issued a warning as long ago as 2015.

The company currently pays Imagination 30 cents per device made, and is expected to reduce this to 10 cents before ceasing payments altogether.

Apple also dismissed Imagination’s claim that it would be impossible for the iPhone-maker to create its own GPU chips without infringing upon its patents.

This latest turn of events is potentially very serious. Any publicly-traded company has a legal obligation to disclose material information that may significantly impact its prospects, and Apple appears to be suggesting that Imagination had some knowledge more than two years before its disclosure.

The two companies are currently going through a dispute resolution process, while Imagination has put itself up for sale.