EN 16931 compliance 

Three levels of compliance

Section 4.4 of part 1 of the eInvoicing standard specifies the compliance criteria in detail but below is a short introduction.

The European eInvoicing standard defines compliance at three levels and states that each party must comply with all levels. This means that a compliant party must have implemented support for invoices that fulfil the requirements of a compliant invoice specification.

The invoice document

The electronic invoice document that is created and sent must comply with all the rules that are defined for the CORE invoice or the CIUS specification that it is based on.

This includes that it:

• shall contain all mandatory information.
• relevant information must be structured as specified.
• amounts must be calculated as specified.
• elements shall only contain allowed values, such as codes.

The implementation

A compliant receiver of an electronic invoice must accept and process all invoices that are sent to him if those invoices are compliant to the European eInvoicing standard CORE data model or to a CIUS. This means that if the sender uses any optional information that is allowed in the CORE or the relevant CIUS he can be sure that the receiver will, in one way or another, process that information as defined in the standard and will not reject having received that information.

A compliant sender is able to create electronic invoices that comply with the European eInvoicing standard or a CIUS.

The CIUS specifications that a particular sender or receiver must or is allowed to use may be restricted by the EU member state in which he is registered, through the member states legal adoption of Directive 2014/55. Information about such restrictions is found in the relevant national legislation but an introduction may be found in the country profiles.

The specification

When an invoice document and its implementation are based on a CIUS, that CIUS must fulfil the criteria stated in section 4.4.2 of EN 16931 part 1. In essence these criteria require that the CIUS is a subset of the CORE and does not break any of the CORE rules. The implication is that anyone who is able to receive the full CORE will also be able to receive and correctly process any compliant CIUS.

Note that does not apply the other way around. Pragmatically, a receiver who is only able to receive a particular CIUS may not be able to receive and process invoices that comply to the CORE or a different CIUS if those invoices use options that have been restricted out of the CIUS that the receiver supports. Implementers are encouraged to avoid complying with the EN by using CIUS's specifications that have a narrow scope and, when using such CIUS specifications for particular purposes, then to also implement support for the full CORE or CIUS specifications that have a wide scope. For information about published CIUS specifications refer to the eInvoicing community driven registry of CIUS.

Other invoice specification

Public entities are required by Directive 2014/55 to be able to receive and process invoices that comply with the European eInvoicing standard. That requirement does not extend to receiving electronic invoices based on other specifications, such as formats used by a particular seller. If sellers offer invoices based on other specification the Public Entity has free choice in how to address that, unless other contracts or legal clauses apply. Neither does Directive 2014/55 require public entities to be only able to receive invoices that comply with the eInvoicing standard. Public entities can continue using existing implementations for receiving electronic invoices for particular purpose or implement new ones along side the ones that comply to the eInvoicing standards.