CEN/TC 434/WG 7 - Extension methodology

This Technical Report describes how trading partners may extend the core invoice model and the related business rules and code lists, in order to support business cases that are specific to their trading environment, while at the same time maintaining semantic interoperability with the core invoice model.
This Technical Report does not define a methodology for creation of core invoice usage specification, nor does it describe the detailed process of syntax binding.

All parts of EN 16931 with a specific focus on CEN/TR 16931-5 (Electronic invoicing - Part 5: Guidelines on the use of sector or country extensions in conjunction with EN 16931-1, methodology to be applied in the real environment).