diff --git a/xml/api/fence-event-2.15.rng b/xml/api/fence-event-2.15.rng
index e54687cd25..8e000cafa5 100644
--- a/xml/api/fence-event-2.15.rng
+++ b/xml/api/fence-event-2.15.rng
@@ -1,33 +1,36 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <grammar xmlns="http://relaxng.org/ns/structure/1.0"
          datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
 
     <start>
         <ref name="fencing-history-event"/>
     </start>
 
     <define name="fencing-history-event">
         <element name="fence_event">
             <attribute name="status">
                 <choice>
                     <value>failed</value>
                     <value>success</value>
                     <value>pending</value>
                 </choice>
             </attribute>
             <optional>
                 <attribute name="extended-status"> <text /> </attribute>
             </optional>
+            <optional>
+                <attribute name="exit-reason"> <text /> </attribute>
+            </optional>
             <optional>
                 <attribute name="delegate"> <text /> </attribute>
             </optional>
             <attribute name="action"> <text /> </attribute>
             <attribute name="target"> <text /> </attribute>
             <attribute name="client"> <text /> </attribute>
             <attribute name="origin"> <text /> </attribute>
             <optional>
                 <attribute name="completed"> <text /> </attribute>
             </optional>
         </element>
     </define>
 </grammar>