The date by which issuers of invoices to the Federal Government had to switch to electronic invoicing was 27 November 2020. Since then, invoice issuers have not been allowed to send invoices in paper form or as PDF files to public-sector customers of the federal administration. (Attachments as PDF files, for instance, can only be submitted if embedded in XML data files.) All invoices sent to the authorities of the federal administration must now be e-invoices as defined in the federal E-Invoicing Ordinance (E-Rechnungsverordnung, ERechV) (exemptions are provided for in section 3 (3) ERechV).