asterisk users - Dec 2006 - comand stun (for what) asterisk 1.4

I'm looking for some doc's what is new in 1.4

in deep for the comand stun debug

neptun:/usr/src/asterik_pgk/asterisk-1.4.0/main # asterisk -rvvvv
Asterisk 1.4.0, Copyright (C) 1999 - 2006 Digium, Inc. and others.
Created by Mark Spencer <markster@digium.com>
Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty'
for details.
This is free software, with components licensed under the GNU General Public
License version 2 and other licenses; you are welcome to redistribute it under
certain conditions. Type 'core show license' for details.
========================================================================  ==
Parsing '/etc/asterisk/asterisk.conf': Found
  == Parsing '/etc/asterisk/extconfig.conf': Found
Connected to Asterisk 1.4.0 currently running on neptun (pid = 4390)
Verbosity is at least 4
neptun*CLI> stun
debug  no
neptun*CLI> stun