diff --git a/reference/json/constants.xml b/reference/json/constants.xml
index 94f0931a17..8546a88a9e 100644
--- a/reference/json/constants.xml
+++ b/reference/json/constants.xml
@@ -154,6 +154,17 @@
     </simpara>
    </listitem>
   </varlistentry>
+  <varlistentry>
+   <term>
+    <constant>JSON_BIGINT_AS_STRING</constant>
+     (<type>integer</type>)
+   </term>
+   <listitem>
+    <simpara>
+     Available since PHP 5.4.0.
+    </simpara>
+   </listitem>
+  </varlistentry>
  </variablelist>
 </appendix>