diff --git a/etc/NEWS b/etc/NEWS
index 5a1863254d4..3091e893297 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1178,10 +1178,12 @@ as a function to call to provide default values.
 The default `crm-separator' has been changed to allow surrounding spaces
 around the comma.
 
-*** The `common-substring' arg of `display-completion-list' is obsolete.
-Either use `completion-all-completions', which returns highlighted
-strings (including for partial or substring completion), or call
-`completion-hilit-commonality' to add the highlight.
+*** The `common-substring' argument of `display-completion-list',
+which has been documented as obsolete since Emacs 23.1, is now _really_
+obsolete, and no longer advertised.  Instead use either
+`completion-all-completions', which returns highlighted strings (including
+for partial or substring completion), or call `completion-hilit-commonality'
+to add the highlight.
 
 +++
 *** New function `completion-table-with-cache' is a wrapper for