diff --git a/appendices/migration54.xml b/appendices/migration54.xml
index d37155fecd..d27e16ef5d 100644
--- a/appendices/migration54.xml
+++ b/appendices/migration54.xml
@@ -258,6 +258,11 @@
      Improved parse error messages and improved incompatible arguments warnings.
     </simpara>
    </listitem>
+   <listitem>
+    <simpara>
+     The session extension can now track the <link linkend="session.upload-progress">upload progress</link> of files.
+    </simpara>
+   </listitem>
   </itemizedlist>
  </section>