diff --git a/htdocs/Tibetan51Errata.html b/htdocs/Tibetan51Errata.html
index d1e892f..948640c 100644
--- a/htdocs/Tibetan51Errata.html
+++ b/htdocs/Tibetan51Errata.html
@@ -135,6 +135,12 @@
     TibetanMachineWeb3.33 through TibetanMachineWeb3.44, inclusive,
     are incorrect.  These should be [0, 124], not [0, 125].
   </li>
+
+  <li>
+    The 'greng-bu vowel glyphs listed for TibetanMachineWeb4.57,
+    TibetanMachineWeb4.58, and TibetanMachineWeb4.59 are incorrect.
+    These should be [0, 123], not [0, 125].
+  </li>
 </ul>
 
 <p>