How to justify a gap in a series' numbering

What is it for?

The numbers in a series of certified documents must follow on without gaps. When a number, or a range of numbers, is missing, it is never filled in: the number is used up. What you can do is record why it is missing, so that the gap appears as justified to whoever checks the numbering. The justification does not touch the series or any document.

When to use it?

• When you imported invoices from the previous program and the imported series has numbers that were never issued (for example, the program skipped numbers when it changed version).
• When a numbering check points to missing numbers and you have already confirmed with your certified accountant why they are missing.

Do not use a justification to hide a document that exists and was not imported: import it.

Where to find it?

Accounting › Configure › Other settings › Numbering gap justifications.

For a fiscaldoo series, that series' justifications can also be seen in the series' Gap justifications tab (Accounting › Configure › Certified invoicing › Fiscal series, open the series).

Before you start

• Your profile is Fiscal officer (or administrator). The steps were done with Certified Accountant / Fiscal Manager with Fiscal officer. The Accountant profile does not have this menu and cannot create justifications.
• Have to hand the document type and the series identifier (in FT 2025/0004, the type is FT and the identifier is 2025), the missing numbers and the proof of the reason (for example, a statement from the previous program's supplier). Decide the reason with your certified accountant.

How to use it

1. Open Accounting › Configure › Other settings › Numbering gap justifications. With no justifications, the list says: “The justifications of numbering gaps appear here. For a series imported from the previous software, create one with New: document type (e.g. FT), series identifier (e.g. 2025), the missing numbers and the reason.”
2. Click New. The Justification of a series numbering gap form opens.
3. For a series imported from the previous program, fill in Document type (previous software) (for example FT) and Series identifier (previous software) (for example 2026). Leave Series empty: it is only for fiscaldoo series.
4. In First number and Last number, type the missing range. For a single number, type the same in both. A justification covers at most 100000 numbers; for more, create several.
5. In Reason, explain what happened to the numbers and where the proof is, so that an auditor can understand it.
6. Check the numbers and the reason and click the save button: the cloud icon at the top, next to the form's name (on hover, it says “Save manually”). Justified by and Justified at are already filled in on the new form, with your name and the date and time. To give up, click the X next to the cloud (“Discard all changes”): nothing is saved. Once saved, the form no longer shows the cloud or the X. If fiscaldoo refuses, the Validation Error window opens with the message and the form stays open (see “Common problems”).
7. Go back to the list: click Numbering gap justifications in the breadcrumb at the top.

Expected result

• The justification appears in the list, with the type, the identifier, the numbers, the reason, Justified by and Justified at. In the demo: FT, 2026, from 3 to 5, recorded by the example profile on 31/10/2026.

• No journal entry is created, and no document changes.

• In the month's billing SAF-T file, the justified numbers no longer count as a gap (example below).

• The integrity report (Audit › Integrity › Check document integrity) only checks fiscaldoo series: an imported series does not appear in it, either before or after the justification. The gap in an imported series can be seen in the importer, in the SAF-T file and on the next screen.

• Audit › Integrity › Integrity and completeness controls shows the gap in an imported series while it has no justification, for the dates chosen in From and Up to. In the demo, with the example profile, from 01/01/2026 to 31/10/2026 and before the justification, the screen counted Differences 1, with the line Numbering gap FT 2026/3-5: “Series FT 2026: numbers 3 to 5 are missing and have no justification.”. In What to do: “This series comes from the previous program. Check whether the document was left out of the import and, if so, import it; if it never existed, use the “Numbering gap justifications” button below and create one with New (document type FT, series 2026, the missing numbers and the reason). Never reuse the number.”. The Numbering gap justifications button, at the bottom of the window, opens the list in this article; it only appears when there is a gap of this kind to justify. With the justification for 3 to 5 recorded, the same screen answered “No differences: the 328 entries of Empresa Demonstração, Lda from 01/01/2026 to 31/10/2026 are balanced, their totals add up, their series are consistent and the signature chain and the numbering are intact.”, without the button. This screen does not tell you whether the SAF-T file passes: check that in the month's billing SAF-T file (example below).

Example: the imported series before and after the justification

In the demo, invoices FT 2026/1, FT 2026/2, FT 2026/6 and FT 2026/7 from the previous program, dated 2 to 5 January 2026, were imported into fiscaldoo. Numbers 3 to 5 were never issued. When validating the file, the importer warned: “Series FT 2026: 3 number(s) missing between 1 and 7: 3, 4, 5.”, but it did not stop the import.

1. Before: Generate SAF-T with F — Invoicing and January 2026 counted 7 documents (the 3 fiscaldoo invoices and the 4 imported ones) and the record became Invalid, with 1 error: “Series "2026" (FT): numbers 3 to 5 are missing between 1 and 7 and have no recorded justification.” The error's suggestion tells you to record the justification in this menu, with type FT, series 2026, the missing numbers and the reason.
2. After: with the justification for 3 to 5 recorded, Regenerate created a new Generated record, with Error Count 0 and Warning count 0. The control note counts the same 7 documents.
3. The accepted gap stays visible. In the new record's messages, fiscaldoo writes: “Numbering: 3 gap(s) in the series were accepted because each one has a recorded justification. Why: a gap with a justification is not an error, but it is shown here so that whoever delivers the file knows it was accepted. See the menu “Numbering gap justifications” for the reasons.” The number counts the accepted missing numbers (3, 4 and 5), not the justifications: in the example there is only one. Before submitting the file, check in the justifications list that every accepted gap has a reason your certified accountant knows about.

The file itself does not change: both records have the same SHA-256, and the file does not carry the justification. What changes is the check made before it can be downloaded. Pending validation by a certified accountant: how the justification of a gap in an imported series is presented to the AT, since the SAF-T file does not carry it.

Important notes

A justification cannot be changed or deleted

Once saved, the justification stays in the audit trail. If you try to change it, fiscaldoo refuses: “A gap justification cannot be changed once recorded: it is part of the audit trail. If it was wrong, keep it and explain in a new justification of other numbers.” It cannot be deleted either. Check the numbers and the reason before saving. Pending validation by a certified accountant: which reasons and which proof are acceptable for a numbering gap in an imported series.

• A number held by a company document, even a cancelled one, is not a gap and cannot be justified (see “Common problems”).
• The steps to import the series and documents from the previous program are not in this article. Checking the numbering of fiscaldoo series is in How to check the integrity of certified documents, and SAF-T file errors in How to fix SAF-T validation errors.

Common problems

All of these appear when you click the save button, in the Validation Error window, and nothing is saved. Click Close: the form stays open with what you typed. Fix it and save again, or click the X to discard. The messages are fiscaldoo's, with series FT 2026 from the example.

The numbers are already justified

• Message: “Numbers 5 to 5 of series "2026" overlap a justification already recorded (3 to 5). A justification cannot be changed or replaced: justify only numbers not yet justified.”
• What to do: justify only the numbers that are not yet in the list.

A document has that number

• Message (imported series): “Numbers 2 to 2 of the series "FT 2026" (previous software) cannot be justified: a document of the company holds at least one of them. Justify only the numbers that no document has.” It also appears when the range includes a number that exists: from 4 to 6, because FT 2026/6 was imported.

• Message (fiscaldoo series): “Numbers 1 to 1 of series "FT D26" cannot be justified: not all of them are gaps (a number held by a document — even a cancelled one — is not a gap). Check the numbering first and justify only the numbers that appear as missing.”

• What to do: check in the documents list which numbers exist and justify only the missing ones.

The numbers are swapped, or start at 0

• Messages: “The last number (7) cannot be before the first (9). Swap them, or enter the same number in both to justify a single number.” and “The numbers of a justification start at 1: 0 to 2 is not a valid range. Enter the first and the last missing number of the series.”
• What to do: fix the numbers and save again.

The series type or identifier is not valid

• Messages: “The document type “XX” is not a document type known to the product. Enter the SAF-T code of the series (for example FT, FR, NC).” and, with no identifier, “Enter the identifier of the series of the previous software (in “FT 2025/0004” it is “2025”), or choose a series of the product.”
• What to do: copy the type and the identifier from the number of a document in the series (in FT 2025/0004, FT and 2025).

The reason is missing

• Message: “A gap justification needs a reason: explain what happened to the number(s) so an auditor can understand it.” A reason with only spaces is also refused.
• What to do: write the reason and where the proof is.

The range is too large

• Message: “A justification covers at most 100000 numbers and this one covers 200001. Split it in several justifications of smaller ranges, each with its reason.”
• What to do: split the range into several justifications.