don't let an error in one envelope from address blow away other
jobs to the same host later in the queue run

fix a problem that was causing inappropriate MIME-encoding

get ORCPT= ESMTP DSN parameter working

some conditions were reversed

convert to new DSN draft

remove Content-Type: header from returned messages if and only if
no body is to be returned -- this could confuse mail readers

accept "ESMTP" anywhere on any line of the greeting message
to force running in Extended mode

tweak EightBitMode and F=8 options to do something useful

add F=8 mailer flag to force "just send 8" behaviour

first cut at DSN implementation

include host name we are chatting with when diagnosing protocol error

MIME 8 to 7 bit support

break out special local mail processing (e.g., mapping to the
"prog" mailer) onto separate mailer flags

fixes for MIME body type support

move 7BIT information from per-mailer to per-connection so it can
be tweaked based on the other end

try to make sure that path-addrs always have <angle brackets>

avoid misleading error message if an SMTP mailer drops core

avoid stupid failures if 421 error is returned during connection startup

avoid having errors on quit requeue the current job -- this is
not sensible under connection caching

give immediate error reply to 5xx greeting message

allow dumping of MCI cache to syslog for debugging

8.6.2: improved error return messages; better error handling on
hung connections or the name server is down; add "vendor code" on V line;
fix some X-Authentication-Warning: problems; portability fixes

comment regarding CheckLoopBack

hooks for future features

react reasonably with negative e_msgsize and SIZE parameter