MIME has sufficient mechanisms to allow extension without changing the
value of MIME-Version.
If the value of MIME-Version ever did change, large sections of the
installed base will break. Particularly notice that the value of
MIME-Version did not change between 1341 and 1521. One of the key
design goals of MIME is that it not break the installed base--MIME did
not "change the version number" of 822.
Changing the MIME version number would break the separation between
type and transfer encoding. Consider a message of MIME version X,
which travels through a gateway conforming to MIME version Y and where
the gateway has to change the transfer encoding. What is the MIME
version of the resulting message?
Mark Crispin's prediction of 23-Dec-91 that MIME-Version would become
superfluous baggage has come true. The amount of superfluous baggage
that it represents should be reasonably minimized.
--
_.John G. Myers Internet: jgm+(_at_)CMU(_dot_)EDU
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