diff --git a/reference/apache/functions/apache-response-headers.xml b/reference/apache/functions/apache-response-headers.xml
index 65ed703b81..afaa6ae1e6 100644
--- a/reference/apache/functions/apache-response-headers.xml
+++ b/reference/apache/functions/apache-response-headers.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.1 $ -->
+<!-- $Revision: 1.2 $ -->
 <!-- splitted from ./en/functions/apache.xml, last change in rev 1.2 -->
   <refentry id="function.apache-response-headers">
    <refnamediv>
@@ -15,7 +15,8 @@
       <void/>
      </methodsynopsis>
     <para>
-     Returns an array of all Apache response headers.
+     Returns an array of all Apache response headers.  This functionality
+     is only available in PHP version 4.3.0 and greater.
     </para>
     <para>
      See also <function>getallheaders</function> and