diff --git a/reference/mongo/mongogridfscursor/key.xml b/reference/mongo/mongogridfscursor/key.xml
index 471a6421b5..4c43827f10 100644
--- a/reference/mongo/mongogridfscursor/key.xml
+++ b/reference/mongo/mongogridfscursor/key.xml
@@ -23,9 +23,36 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;  
   <para>
-   The current result&apos;s filename.
+   The current result&apos;s _id as a string.
   </para>
  </refsect1>
+
+ <refsect1 role="changelog">
+  &reftitle.changelog;
+  <para>
+   <informaltable>
+    <tgroup cols="2">
+     <thead>
+      <row>
+       <entry>&Version;</entry>
+       <entry>&Description;</entry>
+      </row>
+     </thead>
+     <tbody>
+      <row>
+       <entry>1.3.0</entry>
+       <entry>
+        The document's <literal>_id</literal> is returned as a string value,
+        since the key should be unique. Pre-1.3.0, <literal>filename</literal>
+        was returned.
+       </entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </informaltable>
+  </para>
+ </refsect1>
+
 </refentry>
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