When an application has ideas for enhancing the messaging experience, who governs those changes? What if an application refuses to incorporate those changes, or refuses to make those changes interoperable?

And who decides which application(s) are forced to implement those enhancements?

For example, iMessage supports iMessage apps. I imagine providing interoperability for those would be a monumental task, if not impossible. Would Apple now be forced to abandon its iMessage app store due to lack of interoperability?

Or does this new law apply only to the core tenants of a message application? That a message app must only be interoperable with other apps/services in the sense that it can send and receive basic text?