Microsoft has backed “Fortnite” video game maker Epic Games in its legal battle with Apple – alleging in a new court filing that the Tim Cook-led tech giant has “stymied” its own efforts to create an Xbox mobile store.

The court ruling makes it possible for Microsoft to now launch its Xbox mobile store, but it’s clear that the software giant also wants to ensure Apple’s appeal against the ruling isn’t successful. If Microsoft did launch its Xbox mobile store and then Apple won a temporary stay, it may have to pull that store pending the appeal process.

Microsoft filed an amicus brief supporting Epic Games' fight against Apple over its control over the App Store.