Peppol’s capabilities for reporting back on the status of e-invoice transmissions and processing provide useful information for many organisations. This currently exists on three levels:
- MDN – Message Disposition Notification
- Occurrence: always
- Response: synchronous
- Type of feedback: technical
- Purpose: indicates whether or not the document has successfully arrived at the receiving Access Point
- MLR – Message Level Response
- Occurrence: optional
- Response: asynchronous
- Type of feedback: technical
- Purpose: confirmation that document content has been technically validated, or report of failure and reason(s) why, e.g. non-compliance with UBL validation rules, invalid invoice
- IMR – Invoice Message Response
- Occurrence: optional
- Response: asynchronous
- Type of feedback: business process status, e.g. acceptance/rejection of invoice, invoice paid
While MDN is a standard Peppol procedure for all e-invoice transmissions that happens by default, MLR and IMR are only possible if the set-ups around the relevant sending and receiving Access Points are suitable. There is, therefore, no guarantee of being able to get MLRs and IMRs for transactions with different parties.
The problem with Peppol MLR and IMR
The benefits of knowing whether e-invoices have been received, technically validated, accepted and paid are clear. But in practicality, there’s often a problem relaying this information. And it comes down to a very simple thing: how organisations are identified for MLR and IMR communications within Peppol.
If an organisation uses different solutions for sending e-invoices and receiving e-invoices via Peppol, each needs its own ID for receiving MLR and IMR communications. But Peppol only allows every connected participant to have one ID for this purpose, and IDs cannot be reassigned. So, if the organisation’s MLR / IMR ID has already been assigned to its e-invoice receipt endpoint, it cannot have another ID at its e-invoice sending endpoint. And that means there’s nowhere for MLR and IMR feedback on the status of sent invoices to land.
A simple solution is on the way
A dedicated Peppol workgroup is currently discussing proposals for Message Level Acknowledgement (MLA), which would enable response to a reply-to address embedded within each transmitted document (added to the SDBH header). This will eliminate the need to assign all of an organisation’s responses to its single Peppol ID, and will simplify the invoice feedback process.
An RFC proposal to replace MLR and IMR with MLA was submitted to the OpenPeppol eDelivery Change Management Board (eDEC CMB) in March 2024.
What the MLA proposal means for software developers
While the timeline for introducing MLA is not yet known, we would expect it to be within the next few months. On this basis, we would advise any software developers who are tying themselves in knots trying to work around the MLR and IMR ID issue to stop and wait, as these mechanisms will become obsolete.