The European Commission published the final report of the expert group in E-Invoicing:
Cornerstones of the report are the XLM format for invoices based on UNCEFACT/CII 2 (http://www1.unece.org/cefact/platform/display/TBG/Cross+Industry+Invoice+Process) and the skippping of requirements for authentification and integrity of electronic invoices (like Electronic Signatures). In the past, in countries like Germany, electronic invoices were mailed as PDF and had to have a qualified electronic signature due to taxation laws.
There is a thread in our group "Information & Document Management" in German language discussing the consequences for the qualified electronic signature, tax abuse, integrity and authentification issues in Germany:
https://www.xing.com/net/informationlifecyclemanagement/legal-aspects-of-information-document-management-265/de-elektronische-rechnungen-ohne-elektronische-signatur-26362422/26362422/#26362422
Ulrich Kampffmeyer

>>>>>link correction