No, the question is neither of those. The question is how to define the cutoff in a portable way that enables interoperability and long-term stability. A docume

No, the question is neither of those. The question is how to define the cutoff in a portable way that enables interoperability and long-term stability. A document format where every implementation has its own secret cutoff that also probably changes all the time is just idiotic if your goal is interoperability.