diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index 7a6a508bb5..78108fb9db 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -170,6 +170,13 @@ int f(vector<map<int, double>>);
 
   </li>
 
+  <li>Clang's <tt>-fcatch-undefined-behavior</tt> option has grown the ability
+  to check for several new types of undefined behavior.
+
+  <!-- Flesh this out prior to release. -->
+
+  </li>
+
 </ul>
 
 <h4 id="tlsmodel">Support for <code>tls_model</code> attribute</h4>