The latest version of the XRechnung standard must always be used when issuing e-invoices. Another standard (e.g. ZUGFeRD 2.1.1 XRechnung profile without PDF visual format, as a purely structured XML file) can also be used if it complies with the requirements of the European standard for electronic invoicing (EN-16931), the Federal Government’s Regulation on Electronic Invoicing (E-RechV) and the Federal Government’s terms of use for the invoice submission platforms.
Invoice formats that do not comply with the requirements of the European standard cannot be taken into account.
Invoice supporting documents or attachments must be embedded in the invoice data record and may not be sent separately as an attachment to an email or De-Mail.
The maximum permissible size of an invoice depends on the transmission channel selected (e.g. for ZRE: 10 MB for email attachments or 11 MB for attachments in the web entry). Please refer to the terms of use of the platform. The maximum number of embedded documents supporting the invoice is limited to 200. Permitted file types of the embedded documents are: ‘png’, ‘pdf’, ‘jpg’, ‘jpeg’, ‘xlsx’, ‘ods’ and ‘csv’.“. Attachments may not contain active content (e.g. macros). Changes to these restrictions will be announced via the invoice receipt platforms.
Invoice documents with attachments that require paper-based submission under other legal provisions (export certificates, customs documents, etc.) remain unaffected by the above regulations.
More detailed information on the XRechnung standard can be found at KoSIT.