+PH/04 There is a new option called acl_not_smtp_mime that allows you to scan
+ MIME parts in non-SMTP messages. It operates in exactly the same way as
+ acl_smtp_mime
+
+PH/05 It is now possible to redefine a macro within the configuration file.
+ The macro must have been previously defined within the configuration (or
+ an included file). A definition on the command line using the -D option
+ causes all definitions and redefinitions within the file to be ignored.
+ In other words, -D overrides any values that are set in the file.
+ Redefinition is specified by using '==' instead of '='. For example:
+
+ MAC1 = initial value
+ ...
+ MAC1 == updated value
+
+ Redefinition does not alter the order in which the macros are applied to
+ the subsequent lines of the configuration file. It is still the same
+ order in which the macros were originally defined. All that changes is
+ the macro's value. Redefinition makes it possible to accumulate values.
+ For example:
+
+ MAC1 = initial value
+ ...
+ MAC1 == MAC1 and something added
+
+ This can be helpful in situations where the configuration file is built
+ from a number of other files.
+
+PH/06 Macros may now be defined or redefined between router, transport,
+ authenticator, or ACL definitions, as well as in the main part of the
+ configuration. They may not, however, be changed within an individual
+ driver or ACL, or in the local_scan, retry, or rewrite sections of the
+ configuration.
+