Decree-Law 28/2019 · State Budget 2027
Qualified signatures on invoices: another year, and how ERPs are adapting
- Who it affects
- Companies sending PDF invoices to customers in Portugal.
- What changes
- PDF without a qualified signature is accepted until 31 December 2026. The 2027 Budget proposal would extend it one year.
- D365FO impact
- A stored final document to sign, and a company certificate held outside the ERP.
I wrote earlier about the qualified electronic signature requirement for invoices (the 1 January 2027 deadline). Things have moved since then, so here is a short update.
Where it stands
The legal base is Decree-Law 28/2019, article 12. When an invoice is issued electronically, with the customer’s prior acceptance, its authenticity and integrity must be guaranteed. The decree lists three ways to do it: a qualified electronic signature, a qualified electronic seal under the eIDAS regulation, or an EDI agreement between the parties. The list is introduced with “namely”, so in theory it is not closed, but these are the three options the market works with.
PDF invoices without a qualified signature have been accepted until 31 December 2026 under the 2026 State Budget.
A new proposal is on the table. The 2027 State Budget proposal (Proposta de Lei 110/XVII), delivered to Parliament on 8 October 2026, would accept PDF invoices until 31 December 2027. The same proposal would move the annual SAF-T accounting file again, to periods from 2028, first filed in 2029. According to the sources I found, debate starts on 27 and 28 October and the final vote is planned for 24 November. It is a proposal. Until it is published as law, I would not plan around it.
How software vendors are dealing with it
I read what a few public vendor pages say.
- Some e-invoicing providers take the invoice data, convert it to a structured format such as UBL, XML or EDIFACT, apply a qualified signature, and send a PDF representation to customers who do not use EDI.
- Some Portuguese invoicing programs say you install a qualified certificate once and every document is signed from then on.
Both approaches have one thing in common. The signature is applied to a final document, after the ERP has produced it.
What Dynamics 365 offers
D365 Finance and Operations has a feature called electronic signatures. It is about users approving changes, with a certificate per user. It is not the same thing as signing an invoice with a company certificate.
The Electronic invoicing service is closer. Its documentation describes certificates kept in Azure Key Vault and chains of certificates used to apply digital signatures. I did not find a public Microsoft page that says how this applies to the Portuguese requirement, so I would not assume it does.
Questions that stay the same, whatever the date
- Signature or seal? A qualified signature belongs to a person. A seal belongs to a company. For invoices, the seal looks like the natural fit, but that is a decision for the company and its legal advisor.
- Which file is the invoice? If a PDF is created fresh every time someone prints, there is nothing stable to sign. You need one stored final document.
- Where do the keys live? Who can use the certificate, and what happens when it expires?
- Does the customer accept electronic invoices? The rule applies when they have agreed to it.
An extra year helps. It does not remove these questions.
Sources: EDICOM, qualified electronic signature in Portugal, Artsoft, digital signature on invoices, MarcaWeb on the 2027 Budget proposal, Microsoft Learn, electronic signatures, Microsoft Learn, Electronic invoicing parameters.