[IBR-156-OM] - Import date (BTOM-020) MUST be formatted YYYY-MM-DD and be a valid date.
IBR-156-OMubl:Invoice | cn:CreditNotenot(cac:Delivery/cac:Shipment/cac:Delivery/cbc:ActualDeliveryDate) or (matches(cac:Delivery/cac:Shipment/cac:Delivery/cbc:ActualDeliveryDate, '^\d{4}-\d{2}-\d{2}$') and cac:Delivery/cac:Shipment/cac:Delivery/cbc:ActualDeliveryDate castable as xs:date)