In this discussion I don't think it has been pointed out that
quoted-printable generally is not in the Content-Type: field, which is
where one usually specifies ASCII, and other character sets.  Rather, it
generally is in the Content-Transfer-Encoding: field, where one specifies
7bit, 8bit, quoted-printable, etc.

An ASCII text/plain message sent as quoted printable is not a
contradiction.  Different parameters set in different places.

IF you have an email system which automatically knows best and overrides
your settings, well ...

You want all your email to be plain ASCII then set that as Content-type:
and set Content-Transfer-Encoding: to 7bit (not 8bit, nor anything else).
And set your email system so it doesn't override your settings without
permission.

Douglas Winship   [log in to unmask]