Provide the format for the contract date

Error FX-SCH-A-001031 Factur-X

Attribute '@format' is required in this context.

Mandatory rule: As long as it is violated, the invoice is invalid and will be rejected by validators.
What is wrong

The @format attribute is missing from qdt:DateTimeString for the referenced contract.

What the rule means

The format attribute indicates how to interpret the date value in qdt:DateTimeString.

Please provide the contract date format

The format is missing from the date of the referenced contract. Add the @format attribute to qdt:DateTimeString.

What to do
  1. Open the date in ram:ContractReferencedDocument.
  2. Add the @format attribute to qdt:DateTimeString.
  3. Generate the invoice again and validate it.
What it looks like
✗ Triggers the message 
<qdt:DateTimeString>20261003</qdt:DateTimeString>
✓ Correct 
<qdt:DateTimeString format="">20261003</qdt:DateTimeString>
Technical details

The check requires the @format attribute to be present on qdt:DateTimeString.

Where the rule applies

The rule applies to the date of the referenced contract in ram:ContractReferencedDocument.

Context (rule/@context)
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:IncludedSupplyChainTradeLineItem/ ram:SpecifiedLineTradeAgreement/ram:ContractReferencedDocument/ram:FormattedIssueDateTime/ qdt:DateTimeString
Test expression (assert/@test)
@format