diff --git a/xep-0373.xml b/xep-0373.xml
index 4cad2eed..fde57cf9 100644
--- a/xep-0373.xml
+++ b/xep-0373.xml
@@ -268,7 +268,7 @@
         <td>&sign;</td>
         <td>MAY NOT contain one</td>
         <td>MUST have exactly one</td>
-        <td>NOT REQUIRED</td>
+        <td>OPTIONAL</td>
         <td>MUST have exactly one</td>
       </tr>
       <tr>