@epilanthanomai That's my understanding. I think my outside worry is that someone somewhere will attempt to redefine some "document standard" that says all well-formed documents have an M or an F, and issuing guidance that X documents are either improper and/or may be seized as potentially counterfeit. But X markers themselves are the result of a lawsuit that mus have some kind of binding result, so they're likely not in a hurry on that.