Your shipper tax registration numbers were only sent to DHL. They are now also sent to FedEx, UPS, and Japan Post international shipments.
Supported carriers per number are shown in Settings, under Tax registration numbers:
UK VAT and Australia AUSid GST (ABN): DHL, FedEx, Japan Post
NZ IRD, Norway VOEC, Singapore GST, Malaysia LVG: DHL, FedEx, UPS, Japan Post
Each number is only sent when you create a label for the corresponding country. Nothing to change on your side — numbers already registered are used automatically.
