diff --git a/xep.ent b/xep.ent
index cdf6d6fc..fd5b295e 100644
--- a/xep.ent
+++ b/xep.ent
@@ -65,6 +65,8 @@ THE SOFTWARE.
 
 <!ENTITY UNAVAILABLE "&lt;presence type='unavailable'/&gt;">
 
+<!ENTITY ERROR "&lt;error/&gt;">
+
 <!-- notes about namespace versioning -->
 
 <!ENTITY VNOTE "(see <link url='#registrar-versioning'>Namespace Versioning</link> regarding the possibility of incrementing the version number)">