Hello,
the code for generating ODT file are in files like:
/htdocs/core/modules/facture/doc/doc_generic_invoice_odt.modules.php
In this case, this is about invoice (facture).
For shipment, I presume that the module is livraison, but I don’t find file for ODT, only PDF. Thus I presume that it is a generic substitution which occurs.
I’m not sure that the solution can be only transferring files.