There is no data entity allowing us to bulk update the Valid Collection Letter Code held against customer transactions. This is especially relevant for data migration as it needs to be ensured that D365FO starts generating collection letters using the correct code. I.e. in the legacy system, letter 1 was generated for an invoice. Upon data migration the default D365FO value for the collection letter code will be 'None'. This means D365FO would incorrectly generate letter 1 again. Therefore, there needs to be a data entity to mass update these to the correct code. Manual update is of course possible, but not viable for data migration with a large number of invoices.