From the text of the injunction: > [Apple] are hereby permanently restrained [..] from prohibiting developers from including in their apps [..] buttons [,..]

From the text of the injunction: > [Apple] are hereby permanently restrained [..] from prohibiting developers from including in their apps [..] buttons [,..] that direct customers to purchasing mechanisms [..] I'm not sure how exactly to interpret that but it seems reasonable to interpret that has being able to put a button in your app that takes someone to a checkout page.