I'm pretty confused by the suggestion, by you and Ned Freed, that
recipients rely on content-based version fields, since that suggestion
seems to be counter to how I interpreted what the document said.
If I want to send you a Postscript-2 document (say, with a JPEG
compressed image), can I use the "ps" content-type? Is that
legitimate, as long as the enclosed postscript file is clearly marked
internally?
Say, in a couple of years, I want to send you a GIF94b image which
includes a little animation and a audio description of the image --
can I use the "gif" content-type? Presuming of course that GIF94b
format is somehow 'upward compatible' with GIF89a?
Recentmessages from you and Ned Freed seem to indicate that you prefer
not to use versions at all, and that we should rely on markers within
the content of the body to detect different versions. That is, the
"ps" body-type will be used for postscript now, and for postscript
later; the "gif" body-type might well be redefined to include "GIF94b"
at some later date, and that will be OK because readers will be able
to detect that it isn't GIF89a and act accordingly.
Yet, in another discussion, I got the impression that when you say
"ps", what you really mean is "postscript version 1 as defined only by
the 1985 book", and that if I wanted to use Postscript version 2, I'd
have to use a different content-type marker, e.g., "ps2" or "gif94b".
I don't think you can have it both ways. Could you please clarify what
you intend?