diff --git a/CHANGES b/CHANGES
index aa842ebe75..5e64e6ce91 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+5715.	[func]		Add a check when the *-source(-v6) clashes with the
+			global listening port. Such a configuration was already
+			forbidden, but it failed silently. [GL #2888]
+
 5714.	[bug]		Remove the "adjust interface" mechanism that
 			set up a listener on interfaces where the *-source(-v6)
 			address and port were the same as the listening
diff --git a/doc/notes/notes-current.rst b/doc/notes/notes-current.rst
index 2249131d1d..4fa678efa1 100644
--- a/doc/notes/notes-current.rst
+++ b/doc/notes/notes-current.rst
@@ -46,6 +46,18 @@ Feature Changes
   engine is already available in BIND 9; please see the ARM section on
   PKCS#11 for details. :gl:`#2691`
 
+- ``named`` and ``named-checkconf`` now issue a warning when there is a single
+  configured port in the ``query-source``, ``transfer-source``,
+  ``notify-source``, and ``parental-source``, and/or in their respective IPv6 counterparts.
+  :gl:`#2888`
+
+- ``named`` and ``named-checkconf`` now return an error when the single configured
+  port in the ``query-source``, ``transfer-source``, ``notify-source``,
+  ``parental-source``, and/or their respective IPv6 counterparts clashes with the
+  global listening port. This configuration is no longer supported as of BIND
+  9.16.0 but no error was reported, although sending UDP messages
+  (such as notifies) would fail. :gl:`#2888`
+
 Bug Fixes
 ~~~~~~~~~