Year End: The Invoice Series Checklist
What to prepare in December so January's first sale lands in the right series, with a valid ATCUD, and with no credit notes in the first days of the year.
Every year the same thing happens, to the same people, in the same week: January's first sale comes out numbered in last year's series, or comes out with no ATCUD, and somebody spends the 2nd issuing credit notes.
Twenty minutes in December avoids it.
Who this is for (and who it is not)
Only people using yearly series: 2026FR, 2026A, and so on. Anyone on a continuous series (FR, no year) filed it once and has nothing to do at the turn.
If you are not sure which you have, look at the identifier on the last invoice you issued. If the year is in there, this is for you. The difference between the two approaches is covered in Invoice series.
The right order
Next year's series is prepared in December. By January it is already too late for the first sale.Notice that the first three steps all happen in December. 1 January is not when you start: it is when it has to be done.
The checklist
1. List the document types you will issue
It is not one series, it is several. A typical shop issues at least:
- FR or FT, the sale.
- NC, refunds and cancellations.
- RC, receipts, if you invoice on credit.
Each needs its own filed series for the new year. The credit note is the one most often forgotten, because in December nobody is thinking about refunds, and January's first refund always arrives.
2. Create the series in the software
With the name you will use all year and a starting number of 1. Step by step per software: InvoiceXpress, Moloni, Vendus.
Keep last year's convention. Moving from 2026FR to FR2027 breaks nothing, but it forces you to explain the difference to whoever audits you.
3. File it and keep the validation code
By webservice from the software, or by hand on the Portal das Finanças. Each document type is a separate filing and returns its own code.
Keep the codes somewhere outside the software. On the day you need to check one, it beats going back to the portal.
4. Point the integrations at the new series
The step that fails most, because it is the only one that does not live in the invoicing software.
If your shop or your payments run through an integration, the series is written into its configuration. Creating the new series in InvoiceXpress or Moloni does not change the integration: it keeps sending documents to the 2026 series until somebody goes in and changes it.
Places to check:
- The integration for each payment source (shop, Stripe, bookings).
- Tag or customer-type rules, if you use them. They usually carry a series of their own.
- Any automation issuing documents from outside.
5. Make the new series the default
And deactivate the old one after the year's last document is issued. Not before: a series deactivated on 30 December leaves you unable to invoice the sale on the 31st.
6. Issue a test document in January
The year's first document, on the 1st or 2nd, and look at it properly:
- The identifier carries the new series and number
1. - The ATCUD is there, with the new validation code, not last year's.
- The QR Code is there.
If something is wrong, there is still only one document to fix.
December refunds
A December sale refunded in January is credited by a January credit note, in the new credit note series. The credit note references the original document, which is from 2026, and that is exactly right.
What you do not do is reopen the old series in January "for consistency". The date decides.
Common mistakes
- Creating the series and not filing it. It sits there, looking fine, issuing without an ATCUD.
- Filing only the invoice series. The year's first refund fails.
- Forgetting the integration. The software is right and the invoices keep coming out of the old series.
- Deactivating the old series too early. You are left unable to invoice the last days of December.
- Leaving it to 2 January. It is a bank holiday across half of Europe and the tax authority has the same traffic as everyone else.
How Rioko helps
Rioko reads the series straight from your account, so the new one shows up in the dashboard as soon as you create it. You do not have to type it by hand or get the identifier exactly right.
Before the turn, the dashboard warns you that the connection is still pointing at a series from last year. And if a January sale arrives while the connection still points at a series that no longer serves, issuing stops and tells you, instead of numbering in the wrong place.
Frequently asked questions
When should I create next year's series?
In December, before January's first sale. Create it, file it with the tax authority and point the integrations at it: three steps, in that order.
I use a continuous series. Do I have to do anything?
No. A series without a year in it was filed once and never needs touching again. This only applies to yearly series.
I created the new series in the software. Does the integration start using it?
No. The series is written into the integration's configuration and keeps pointing at last year's until somebody changes it. It is the step that fails most.
When do I deactivate last year's series?
After the year's last document is issued, never before. A series deactivated on 30 December leaves you unable to invoice on the 31st.
A December sale refunded in January is credited in which series?
In January's credit note series. The credit note references the original document from the previous year, and that is correct.
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