# PEPPOL-T76-R004

Source: https://xmlvalid.com/rules/PEPPOL-T76-R004

> If both delivery period start date and delivery period end date are given then the end date SHALL be later or equal to the start date.

- Level: error
- Rule sets: Peppol Order Response rules 3.2
- Context: `cac:PromisedDeliveryPeriod | cac:OrderLine/cac:LineItem/cac:PromisedDeliveryPeriod`
- Test: `(exists(cbc:EndDate) and exists(cbc:StartDate) and (cbc:EndDate) >= (cbc:StartDate)) or not(exists(cbc:StartDate)) or not(exists(cbc:EndDate))`

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