In Moment, we have supported EHF 2.0 for a long time. By January 1. 2020, we are required by Norwegian law to support the next version, EHF 3.0.
First, some concepts and abbreviations:
Elektronisk Handelsformat. Version 3 is basically a re-branding of the European standard "PEPPOL BIS Billing 3.0". See EHF Post-Award for useful info from Difi, as well as this brief documentation page with an example of an EHF 3 XML file at the bottom.
Pan-European Public Procurement. This is a set of specifiactions related to invoicing and other types of business-to-business communication.
PEPPOL BIS Billing 3.0
Electronic invoices that can be used in Norway, and in an increasing number of European countries. This is basically a pretty complex XML file with all the details of an invoice. The difference between EHF v. 2, or old standard, and PEPPOL BIS Billing 3.0 is not huge.
Universal Business Language. This is the underlying XML standard that the PEPPOL specifications is based on.