+PP/19 Renamed DNSSEC-enabling option to "dns_dnssec_ok", to make it
+ clearer that Exim is using the DO (DNSSEC OK) EDNS0 resolver flag,
+ not performing validation itself.
+
+PP/20 Added force_command boolean option to pipe transport.
+ Patch from Nick Koston, of cPanel Inc.
+
+JH/15 AUTH support on callouts (and hence cutthrough-deliveries).
+ Bugzilla 321, 823.
+