/// <summary>
 /// Tweak old XMP: Move an instance ID from rdf:about to the
 /// <em>xmpMM:InstanceID</em> property.
 /// </summary>
 /// <remarks>
 /// Tweak old XMP: Move an instance ID from rdf:about to the
 /// <em>xmpMM:InstanceID</em> property. An old instance ID usually looks
 /// like &quot;uuid:bac965c4-9d87-11d9-9a30-000d936b79c4&quot;, plus InDesign
 /// 3.0 wrote them like &quot;bac965c4-9d87-11d9-9a30-000d936b79c4&quot;. If
 /// the name looks like a UUID simply move it to <em>xmpMM:InstanceID</em>,
 /// don't worry about any existing <em>xmpMM:InstanceID</em>. Both will
 /// only be present when a newer file with the <em>xmpMM:InstanceID</em>
 /// property is updated by an old app that uses <em>rdf:about</em>.
 /// </remarks>
 /// <param name="tree">the root of the metadata tree</param>
 /// <exception cref="iText.Kernel.XMP.XMPException">Thrown if tweaking fails.</exception>
 private static void TweakOldXMP(XMPNode tree)
 {
     if (tree.GetName() != null && tree.GetName().Length >= Utils.UUID_LENGTH)
     {
         String nameStr = tree.GetName().ToLower();
         if (nameStr.StartsWith("uuid:"))
         {
             nameStr = nameStr.Substring(5);
         }
         if (Utils.CheckUUIDFormat(nameStr))
         {
             // move UUID to xmpMM:InstanceID and remove it from the root node
             XMPPath path   = XMPPathParser.ExpandXPath(XMPConst.NS_XMP_MM, "InstanceID");
             XMPNode idNode = XMPNodeUtils.FindNode(tree, path, true, null);
             if (idNode != null)
             {
                 idNode.SetOptions(null);
                 // Clobber any existing xmpMM:InstanceID.
                 idNode.SetValue("uuid:" + nameStr);
                 idNode.RemoveChildren();
                 idNode.RemoveQualifiers();
                 tree.SetName(null);
             }
             else
             {
                 throw new XMPException("Failure creating xmpMM:InstanceID", XMPError.INTERNALFAILURE
                                        );
             }
         }
     }
 }