Ever since multi-recipient addressing was introduced, we have had
downgrading, by virtue of users having to choose the least common
denominator approach to sending attachments.
So the fact that this new mechanism allows that downgrading to happen later
in the transmission sequence should not confuse anyone into thinking that
downgrading is a new or unusual requirement.
Dave, it's a gross exaggeration to claim that the fact that human senders have
long found it advantageous to send messages to multiple recipients using a
common format of their choosing, that this is a good justification for
standardizing the idea that MTAs that are responsible to neither the sender
nor the recipient should be able to "downgrade" a message, using arbitrary
and unspecified methods, without any knowledge of the consequence of applying
conversion to the content, and without any explicit authorization.
the use of the RCPT response to tell the client of the recipient's
capabilities
is odd because it asserts that the client intends to deliver a message to
each of several recipients before the client actually knows whether it can
deliver the same version of the message to each recipient, or whether it can
deliver any version of that message to the recipient.
"or whether it can"??? There has been no posting that provides a practical
basis for such a conclusion.
Yes there has, but perhaps you missed it. Regardless you should be able to
figure out that your proposal provides no assurance that downgrading is even
possible. just to take a trivial example - the message might contain only
audio while one recipient accepts only fax. Another example - the recipient
accepts only HTML and plain text, the message is in microsoft word, and while
conversion is possible the MTA doesn't know how to do it.
so yes, "whether it can" is entirely appropriate wording.
Therefore, any implications of this unproved -- and frankly
counter-intuitive and highly unlikely -- assessment has nothing to do with
the current specification.
Dave, the most charitable thing I can say is that you must be living in a
different universe. You have consistently responded to valid, well-explained,
and defensible technical criticisms by flat-out stating that they don't
exist or that they don't make any sense, without any defense. You seem
to think that everyone who uses this extension you're propsing will have
the same assumptions that you do, and adhered to a set of constraints
that exists only in your head. And if you don't understand your own
proposal well enough to make intelligent responses to technical criticism
then frankly you need to withdraw it and stop wasting our time.
Keith