+PH/18 If a system quota error occurred while trying to create the file for
+ a maildir delivery, the message "Mailbox is full" was not appended to the
+ bounce if the delivery eventually timed out. Change 4.67/27 below applied
+ only to a quota excession during the actual writing of the file.
+
+PH/19 It seems that peer DN values may contain newlines (and other non-printing
+ characters?) which causes problems in log lines. The DN values are now
+ passed through string_printing() before being added to log lines.
+
+PH/20 Added the "servers=" facility to MySQL and PostgreSQL lookups. (Oracle
+ and InterBase are left for another time.)
+
+PH/21 Added message_body_newlines option.
+
+PH/22 Guard against possible overflow in moan_check_errorcopy().
+
+PH/23 POSIX allows open() to be a macro; guard against that.
+
+PH/24 If the recipient of an error message contained an @ in the local part
+ (suitably quoted, of course), incorrect values were put in $domain and
+ $local_part during the evaluation of errors_copy.