+PH/04 Added $message_exim_id, ultimately to replace $message_id (they will both
+ co-exist for some time) to make it clear that it is the Exim ID that is
+ referenced, not the Message-ID: header line.
+
+PH/05 Replaced all Tom's calls to snprintf() with calls to the internal
+ string_format() function, because snprintf() does not exist on all
+ operating systems.
+
+PH/06 The use of forbid_filter_existstest now also locks out the use of the
+ ${stat: expansion item.
+
+PH/07 Changed "SMTP protocol violation: synchronization error" into "SMTP
+ protocol synchronization error", to keep the pedants happy.
+
+PH/08 Arrange for USE_INET_NTOA_FIX to be set in config.h for AIX systems as
+ well as for IRIX systems, when gcc is being used. See the host.c source
+ file for comments.
+
+PH/09 Installed latest Cygwin configuration files from the Cygwin maintainer.
+
+PH/10 Named domain lists were not working if used in a queue_smtp_domains
+ setting.
+
+PH/11 Added support for the IGNOREQUOTA extension to LMTP, both to the lmtp
+ transport and to the smtp transport in LMTP mode.
+
+TK/02 Remove one case of BASE64 error detection FTTB (undocumented anyway).
+
+PH/12 There was a missing call to search_tidyup() before the fork() in rda.c to
+ run a filter in a subprocess. This could lead to confusion in subsequent
+ lookups in the parent process. There should also be a search_tidyup() at
+ the end of the subprocess.
+
+PH/13 Previously, if "verify = helo" was set in an ACL, the condition was true
+ only if the host matched helo_try_verify_hosts, which caused the
+ verification to occur when the EHLO/HELO command was issued. The ACL just
+ tested the remembered result. Now, if a previous verification attempt has
+ not happened, "verify = helo" does it there and then.
+
+JJ/01 exipick: added $message_exim_id variable (see 4.53-PH/04)
+
+TK/03 Fix log output including CR from clamd.
+
+PH/14 A reference to $reply_address when Reply-to: was empty and From: did not
+ exist provoked a memory error which could cause a segfault.
+