XML upgrade, VB.NET program need a version update I have booth version, just need little code programming

I have a system developed in delphi 7, which creates an XML, file that must be stamped, currently has the CFDI version 3.3 module working on it, now with version 4.0 I have to make some minimal updates, since my CFDI 3.3 is almost identical to 4.0 but needs adaptation. I have the new module of 4.0 for the creation of XML, we only have to adapt it to how my system is currently, I have both codes, so it is easy to adapt it, I need a programmer who already knows XML, who has already done it or who has the certainty that it can do it, this type of system is basically implemented in Mexico so I prefer a Mexican or Latino programmer