Microsoft attributes the delay of the Xbox mobile app store to Apple's App Store rules, which prevent users from buying Microsoft mobile games through the Xbox web store on iOS.
In an amicus brief supporting Epic Games in their battle against Apple, Microsoft expresses concerns about Apple potentially overturning the injunction allowing payments outside of apps that bypass Apple's 30 percent fee.
Apple has filed an appeal against the injunction and requested the Ninth Circuit to halt enforcement of the ruling, while Microsoft is pushing for enforcement of the injunction during the appeal.
Microsoft aims to launch its own online store for in-app items to work around Apple's restrictions, but Apple's actions could hinder this effort.