https://wccftech.com/epic-games-improbable-setup-25-million/

Yesterday, there was a whirlwind of press release battles between Improbable, the makers of SpatialOS, and Unity. Improbable began by accusing Unity of blocking SpatialOS games due to a change in their Terms of Service, specifically clause 2.4; Unity quickly retaliated and said Improbable’s statement was incorrect, as projects that are already live or in production will be unaffected by this change. They also provided further clarification on the technical matter: developers will be fine as long as their servers are running on a Unity supported platform. If that’s not the case, Unity requires a third-party service to become an approved Unity platform partner.

Only a few hours later, Epic Games seized the opportunity by partnering with Improbable and setting up a $25 million fund to help affected game developers transition from Unity to Unreal Engine.