+PH/03 Added disable_ipv6.
+
+PH/04 Changed $reply_address to use the raw form of the headers instead of the
+ decoded form, because it is most often used to construct To: headers
+ lines in autoreplies, and the decoded form may well be syntactically
+ invalid. However, $reply_address has leading white space removed, and all
+ newlines turned into spaces so that the autoreply transport does not
+ grumble.
+
+PH/05 If group was specified without a user on a router, and no group or user
+ was specified on a transport, the group from the router was ignored.
+
+PH/06 Increased the number of ACL variables to 20 of each type, and arranged
+ for visible compile-time settings that can be used to change these
+ numbers, for those that want even more. Backwards compatibility with old
+ spool files has been maintained. However, going back to a previous Exim
+ release will lost any variables that are in spool files.
+