diff --git a/reference/xsl/constants.xml b/reference/xsl/constants.xml
index b9fcc32a10..f50014712b 100644
--- a/reference/xsl/constants.xml
+++ b/reference/xsl/constants.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.1 $ -->
+<!-- $Revision: 1.2 $ -->
 <section id="xsl.constants">
  &reftitle.constants;
  &extension.constants;
@@ -34,6 +34,50 @@
     </simpara>
    </listitem>
   </varlistentry>
+  <varlistentry>
+   <term>
+    <constant>LIBXSLT_VERSION</constant>
+    (<type>integer</type>)
+   </term>
+   <listitem>
+    <simpara>
+     libxslt version like 10117. Available as of PHP 5.1.2.
+    </simpara>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <constant>LIBXSLT_DOTTED_VERSION</constant>
+    (<type>string</type>)
+   </term>
+   <listitem>
+    <simpara>
+     libxslt version like 1.1.17. Available as of PHP 5.1.2.
+    </simpara>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <constant>LIBEXSLT_VERSION</constant>
+    (<type>integer</type>)
+   </term>
+   <listitem>
+    <simpara>
+     libxslt version like 813. Available as of PHP 5.1.2.
+    </simpara>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <constant>LIBEXSLT_DOTTED_VERSION</constant>
+    (<type>string</type>)
+   </term>
+   <listitem>
+    <simpara>
+     libxslt version like 1.1.17. Available as of PHP 5.1.2.
+    </simpara>
+   </listitem>
+  </varlistentry>
  </variablelist>
 </section>