The documentation for the new UBL.BE version that is based on the EN16931 for e-invoicing.
This version is validated by the Peppol authorities and can also be used to send invoices and credit notes over the Peppol network.
As support for the EN becomes mandatory for public entities as from April 2019, we strongly advise you to update your software according the migration plan put forward by the Peppol community.
More documentation and details on the migration plan for Peppol can be found on http://docs.peppol.eu/poacc/billing/3.0/