move the meta-characters from C0 into C1 space

clean up log levels; allow IDA-style split header/envelope rewriting;
extend arpatounix with more zones (but is this even needed?)

more environment problems; limit resource exhaustion; fix incorrect
name in Connection timed out message; ANSI C fixes; log message sender on
returned mail during queue run; count recipients properly

more environment problems; limit resource exhaustion; fix incorrect
name in Connection timed out message; ANSI C fixes; log message sender on
returned mail during queue run; count recipients properly; fix YP code;
diagnose "message timed out" properly

show more ...

implement arpatounix; log more info; allow nested $?...$|...$.;
POSIX compatibility; handle SMTP MAIL command errors properly;
do early diagnosis of .cf errors; adjust checkpointing; misc bugs

fix botch causing queued headers to have ?XX? prefixes

put return-receipt-to on a conf.c flag (but don't set it);
fix minor syslog problem

Release 6

change random constants to be #defines

add NIS map type; log message-id in same line as from logging

fix auto-quoting screwup

dynamically allocate header fields (and more....); miscellaneous
cleanup (mostly comments)

correct list of must-be-quoted characters

(partially) ANSI-fy it

try to do some syntax error corrections on errors in headers

*really* fix quoting in phrase part of addresses; eliminate #-style
commenting in :include: and .forward files (parenthesized comments
can be used instead)

fix a variety of small bugs noticed by bcx

lint

reduce number of instances of CurEnv by passing it as a parameter

fix latent bug in received logging printing

make eight-bit clean; backslashes are carried through as-is

drop mode a (ARPA FTP) -- NCP is gone forever.....

handle a wider range of syntaxes -- notably, angle brackets
appearing in quotes and comments.

new copyright notice

increase MAXFIELD to 4K; bug report 4.3BSD/usr.lib/153

remove DEBUG