PEPPOL-EN16931-R110

If a line has a period of its own, it must fall inside the invoicing period: the line's start date may not precede the invoice's start date.

Severity: Error
Applies to: CII, UBL
Rule set: v2026-01-31

Official rule text

Start date of line period MUST be within invoice period.

Why does PEPPOL-EN16931-R110 happen?

Back-billing is the classic case: a service from the previous month is picked up on the current invoice and keeps its real period, while the invoicing period covers only the current month.

How do you fix PEPPOL-EN16931-R110?

Widen the invoicing period (cac:InvoicePeriod in the header) so it spans every line, or put the back-billed item on an invoice of its own. What is compared is the line's cbc:StartDate against the header's cbc:StartDate.

In the XML

A UBL fragment. The CII path is named above — same change, different element names.

Fails

<cac:InvoicePeriod>
  <cbc:StartDate>2026-08-01</cbc:StartDate>
  <cbc:EndDate>2026-08-31</cbc:EndDate>
</cac:InvoicePeriod>
<cac:InvoiceLine>
  <cbc:ID>1</cbc:ID>
  <cac:InvoicePeriod>
    <cbc:StartDate>2026-07-15</cbc:StartDate>
  </cac:InvoicePeriod>
</cac:InvoiceLine>

Fixed

<cac:InvoicePeriod>
  <cbc:StartDate>2026-07-01</cbc:StartDate>
  <cbc:EndDate>2026-08-31</cbc:EndDate>
</cac:InvoicePeriod>
<cac:InvoiceLine>
  <cbc:ID>1</cbc:ID>
  <cac:InvoicePeriod>
    <cbc:StartDate>2026-07-15</cbc:StartDate>
  </cac:InvoicePeriod>
</cac:InvoiceLine>

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