-20. If the key for a dnsdb lookup is not an IP address, it is used verbatim,
- without component reversal and without the addition of in-addr.arpa or
- ip6.arpa.
+20. If the key for a dnsdb PTR lookup is not an IP address, it is used
+ verbatim, without component reversal and without the addition of
+ in-addr.arpa or ip6.arpa.
+
+21. Two changes related to the smtp_active_hostname option:
+
+ (1) $smtp_active_hostname is now available as a variable. Its value
+ sticks with the message and is therefore available in routers and
+ transports at delivery time.
+
+ (2) The default for smtp_banner uses $smtp_active_hostname instead
+ of $primary_hostname.