Beginning with V8.7
sendmail, you can set the
EightBitMode option (EightBitMode)
m (mimefy) to force all unlabeled 8-bit mail to
be converted into MIME-labeled mail.
You can suppress this conversion for particular delivery agents by
F=8 delivery agent flag. This form
of suppression has the effect of setting the
EightBitMode option to
(pass8) for an individual delivery agent.