* Partner "Invoiced" smart button changes: Never called; that was for a
  specific Odoo 10 project.
* Invoices & refunds - Show due date: No such changes anymore.
* Invoice validation override: The only changes were:

    * Missing due date filler: Odoo 10 migration defect, got forgotten.
    * Hook to change account-move creation values: No longer needed. Was for
      analytics but xcg/account_analytic_structure supersedes that part.
    * Reference link filler: Moved to xcg/account_move_reference_link.

Superseded by xcg/account_analytic_structure.