For 14 destinations, Japan Post doesn’t use the IOSS number when the recipient pays the duties. Nothing previously indicated this, so you had no way to know the number wasn’t applied.
After creating the label, a warning now appears in the app, and the shipment carries a warning badge in the shipments list, the shipped order page, and the batch list.
This only applies to Japan Post services, and only when an IOSS number is actually sent.
For API users: POST /shipments returns delivery.warnings with ioss_not_accepted.
