10. Variable $smtp_command_history returning a comma-sep list of recent
SMTP commands.
-11. Millisecond timetamps in logs, on log_selector "millisec".
+11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
+ log elements QT, DT and D, and timstamps in debug output.
+
+12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
+ while still in SYN_RECV state; as a client logs when the connection
+ is opened with a TFO cookie. Support varies between platforms
+ (Linux does both. FreeBSD server only, others unknown).
Version 4.89