diff --git a/reference/strings/functions/levenshtein.xml b/reference/strings/functions/levenshtein.xml
index c8c7ae65bc..891b86ec8d 100644
--- a/reference/strings/functions/levenshtein.xml
+++ b/reference/strings/functions/levenshtein.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.2 $ -->
+<!-- $Revision: 1.3 $ -->
 <!-- splitted from ./en/functions/strings.xml, last change in rev 1.12 -->
   <refentry id="function.levenshtein">
    <refnamediv>
@@ -23,12 +23,14 @@
       <methodparam><type>int</type><parameter>cost_rep</parameter></methodparam>
       <methodparam><type>int</type><parameter>cost_del</parameter></methodparam>
      </methodsynopsis>
+     <!-- Callback function not yet implemented, see bug #29552
      <methodsynopsis>
       <type>int</type><methodname>levenshtein</methodname>
       <methodparam><type>string</type><parameter>str1</parameter></methodparam>
       <methodparam><type>string</type><parameter>str2</parameter></methodparam>
       <methodparam><type>function</type><parameter>cost</parameter></methodparam>
      </methodsynopsis>
+     -->
     <para>
      This function returns the Levenshtein-Distance between the
      two argument strings or -1, if one of the argument strings
@@ -59,6 +61,7 @@
      is more general and adaptive than variant one, but not as
      efficient.
     </para>
+    <!--  Callback function not yet implemented, see bug #29552
     <para> 
      The third variant (which is not implemented yet) will be the most
      general and adaptive, but also the slowest alternative.  It will
@@ -118,6 +121,7 @@
      regarding cpu register utilization and cache misses that have
      been worked into the other two variants.
     </para>
+    -->
     <para>
      See also <function>soundex</function>,
      <function>similar_text</function>, and