+33. It is now permitted to omit both strings after an "if" condition; if the
+ condition is true, the result is "true". As before, when the second string
+ is omitted, a false condition yields an empty string. This makes it less
+ cumbersome to write custom ACL and router conditions.
+
+34. Failure to deliver a bounce message always caused it to be frozen, even if
+ there was an errors_to setting on the router. The errors_to setting is now
+ respected.
+
+35. If an IPv6 address is given for -bh or -bhc, it is now converted to the
+ canonical form (fully expanded) before being placed in
+ $sender_host_address.
+