What causes the BR-CO-20 error?

BR-CO-20 occurs when an InvoicePeriod element exists within an InvoiceLine but contains no StartDate (BT-134) or EndDate (BT-135). The period element must have at least one date.

How do I fix BR-CO-20?

Either add dates to the line period (StartDate and/or EndDate), or remove the empty InvoicePeriod element entirely. Invoice Navigator can fix this automatically by removing empty period elements.

Is BR-CO-20 a critical error?

Yes, BR-CO-20 is a business rule violation that will cause invoice rejection. A service period on a line item must have at least one date to be valid.

Can BR-CO-20 be automatically fixed?

Yes! Invoice Navigator automatically removes empty InvoicePeriod elements from invoice lines when no dates are present. This is a safe structural fix with no data loss.

Error codes · EN 16931

BR-CO-20In your invoicing software

Invoice line period dates required

This is the rejection, word for word: „[BR-CO-20] If Invoice line period (BG-26) is used, the Invoice line period start date (BT-134) or the Invoice line period end date (BT-135) shall be filled, or both.“

When cac:InvoicePeriod is present within cac:InvoiceLine, either cbc:StartDate (BT-134) or cbc:EndDate (BT-135) must be provided. An empty InvoicePeriod element violates BR-CO-20.

What to have readyNothing. The file has to be re-exported from your invoicing software; we check it again afterwards.

What we doInvoice Navigator automatically fixes this issue by correcting the `cac:InvoicePeriod` element in your Invoice.

Choose the rejected invoiceor drop it here

XRechnung XML or ZUGFeRD PDF. Checking is free · corrected file €1.90 · the first every 30 days is free · no sign-up.

If you enter it yourself in your invoicing software

Before

<cac:InvoiceLine>
  <cac:InvoicePeriod><!-- invalid or missing value --></cac:InvoicePeriod>
</cac:InvoiceLine>

After

<cac:InvoiceLine>
  <cac:InvoicePeriod>correct-value</cac:InvoicePeriod>
</cac:InvoiceLine>

Element order is part of the rule: if the element sits in the wrong place, the validator rejects with BR-CO-20.

What the finding looks likeExample

FindingStructure invalid · BR-CO-20

Location//cac:InvoiceLine/cac:InvoicePeriod[not(cbc:StartDate) and not(cbc:EndDate)]

From youA re-exported file

ThenRe-export

ProofSHA-256 and /verify link after the check

Often appears together with

BR-CO-18An Invoice shall at least have one VAT breakdown group (BG-23)BR-CO-19Invoice period must have at least one date