diff --git a/CHANGES b/CHANGES
index 52b4cf5e4e..5d20dbea66 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,10 @@
+6184.	[func]		Special-case code that was added to allow GSS-TSIG
+			to work around bugs in the Windows 2000 version of
+			Active Directory has been removed. The 'nsupdate -o'
+			option and 'oldgsstsig' command have been
+			deprecated, and are now treated as synonyms for
+			'nsupdate -g' and 'gsstsig' respectively. [GL #4012]
+
 6183.	[bug]		Fix a serve-stale bug where a delegation from cache
 			could be returned to the client. [GL #3950]
 
diff --git a/doc/notes/notes-current.rst b/doc/notes/notes-current.rst
index b5ba7b17e7..1e3c2e00e9 100644
--- a/doc/notes/notes-current.rst
+++ b/doc/notes/notes-current.rst
@@ -37,7 +37,12 @@ New Features
 Removed Features
 ~~~~~~~~~~~~~~~~
 
-- None.
+- Special-case code that was originally added to allow GSS-TSIG to work
+  around bugs in the Windows 2000 version of Active Directory has now
+  been removed since Windows 2000 is long past end-of-life.
+  The ``nsupdate -o`` option and the ``oldgsstsig`` command to ``nsupdate``
+  have been deprecated, and are now treated as synonyms for ``nsupdate -g``
+  and ``gsstsig`` respectively. :gl:`#4012`
 
 Feature Changes
 ~~~~~~~~~~~~~~~