diff --git a/Documentation.html b/Documentation.html
index 6d70f3d78..4e0476185 100644
--- a/Documentation.html
+++ b/Documentation.html
@@ -58,7 +58,8 @@
 <ul><li><b>PHP</b>
         <ul><li>You need PHP 5.2.0 or newer, with <tt>session</tt> support
                 (<a href="#faq1_31">see
-                <abbr title="Frequently Asked Questions">FAQ</abbr> 1.31</a>)
+			<abbr title="Frequently Asked Questions">FAQ</abbr> 1.31</a>)
+		and the Standard PHP Library (SPL) extension.
                 </li>
             <li>You need GD2 support in PHP to display inline
                 thumbnails of JPEGs (&quot;image/jpeg: inline&quot;) with their