Microsoft says Apple's App Store rules are to blame for the continued delay of the Xbox mobile app store it announced last summer. In an amicus brief filed this week first spotted by The Verge, Microsoft expressed support for Epic Games in the company's long-running bout against Apple.

Microsoft is siding with Epic Games in the legal battle against Apple's App Store "tax," arguing in a new legal brief that Apple has "stymied" Microsoft's planned launch of an Xbox game store.A year ago,

Microsoft claims that Apple's App Store-related court battle with Epic Games interfered with the Redmond firm's plans to launch the Xbox mobile web store.