In ext-base-debug.js beginning at line 2186 the following change was made. Is this correct? Can someone explain why this was done?

3.4.1
Code:
Ext.lib.Ajax = function() {
     var activeX = ['Msxml2.XMLHTTP.6.0',
                   'Msxml2.XMLHTTP.3.0',
                   'Msxml2.XMLHTTP'],
3.4.1.1
Code:
Ext.lib.Ajax = function() {
     var activeX = ['Msxml2.XMLHTTP.3.0',
                   'Msxml2.XMLHTTP'],
Thanks.