diff --git a/appendices/migration70/changed-functions.xml b/appendices/migration70/changed-functions.xml
index 0e71cd6261..8d01d10a3a 100644
--- a/appendices/migration70/changed-functions.xml
+++ b/appendices/migration70/changed-functions.xml
@@ -55,6 +55,12 @@
      functions have NULL byte protection now.
     </simpara>
    </listitem>
+   <listitem>
+	<simpara>
+	 <function>substr</function> now returns an empty string, if string is equal
+	 to start characters long.
+	</simpara>
+   </listitem>
   </itemizedlist>
  </sect2>