Engine firm Unity and cloud tech start-up Improbable have had a very public falling out.

The spat began yesterday when Improbable said that Unity had made changes to its Terms of Service which blocked developers using its SpatialOS tech from the engine.

Unity has since responded, saying Improbable's version of events is incorrect. The firm says this is the result of a negotiation with the London startup and that projects using Unity and SpatialOS will not be affected.

The middleware company also alleges that Improbable has been in violation of its Terms of Service for over a year and that this has been raised with the company several times.

The firm also says that the Terms of Service were tweaked as the language concerning cloud and streaming services was somewhat vague but has been changed to only support approved platforms.

"We believe that even though Improbable is violating our EULA, game developers should never pay the price for that," Unity wrote.

"We have been clear with Improbable that games currently in production and/or games that are live are unaffected, and we would have expected them to be honest with their community about this information. Unfortunately, this information is misrepresented in Improbable’s blog.

"We are genuinely disappointed that we have been unable to come to an agreement with Improbable, and their improper use continued until we took the action we did."

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