diff --git a/ChangeLog b/ChangeLog
index 6092721cad1b10367216f689969cf4ae36ab35f2..48ba14a6191eeb273d8dea63e8e56904117f15f3 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2005-11-10  Kevin P. Fleming  <kpfleming@digium.com>
 
+	* configs/voicemail.conf.sample (format): add strong warning about changing format list when mailboxes contain messages (issue #5689)
+
 	* many files: ensure that system headers are included before Asterisk headers (issue #5693)
 
 	* channels/chan_iax2.c (complete_iax2_show_peer): don't return from function without releasing lock (issue #5685)
diff --git a/configs/voicemail.conf.sample b/configs/voicemail.conf.sample
index 696ce48ebce7930a3e7f1fb5a7fc2e81bdfebbcf..69b145dfc77e6d2d6c0ceeac24bada42e4a9eed6 100755
--- a/configs/voicemail.conf.sample
+++ b/configs/voicemail.conf.sample
@@ -5,6 +5,20 @@
 ; Default formats for writing Voicemail
 ;format=g723sf|wav49|wav
 format=wav49|gsm|wav
+;
+; WARNING:
+; If you change the list of formats that you record voicemail in
+; when you have mailboxes that contain messages, you _MUST_ absolutely
+; manually go through those mailboxes and convert/delete/add the
+; the message files so that they appear to have been stored using
+; your new format list. If you don't do this, very unpleasant
+; things may happen to your users while they are retrieving and
+; manipulating their voicemail.
+;
+; In other words: don't change the format list on a production system
+; unless you are _VERY_  sure that you know what you are doing and are
+; prepared for the consequences.
+;
 ; Who the e-mail notification should appear to come from
 serveremail=asterisk
 ;serveremail=asterisk@linux-support.net