Thomas Fillis reports from Barcelona:

CEN/TC 434 unanimously agreed to endorse UBL and CII as the syntaxes complying with the forthcoming EN and to be listed in a specific CEN Technical Specification (TS). Once the EN and TS are published by CEN and referenced in the  Official Journal of the European Union (OJEU), contracting authorities and entities in the EU will have to receive and process electronic invoices which comply with the EN and any of the two syntaxes, in accordance with the provisions of Article 7 of Directive 2014/55/EU.