And, if all the related party has negotiated well in advance, we might
be able to interoperate.
That's ISO's way of the interoperation.
If you are complaining that we don't have a 0-255 transparent end-to-end
mail transport,
No.
But MIME is a message format. It is not a mail transport. It does not
make any transport related guarantees because that is outside of its
scope.
MIME does define how CTEs should be.
I think we need a mail transport that guarantees 0-255 end-to-end
transparency. But the fact that we don't have one yet is not due
to any fault in the MIME spec.
That's SMTP issue and 8BITMIE is 0-255.
Masataka Ohta