Mandatory attribute. Use BT-5

Usage
Mandatory
Example value
EUR
Code lists
ISO 4217 Currency codes
Rules
Identifier/Error message Flag
PEPPOL-EN16931-CL007
Currency code must be according to ISO 4217:2005
fatal
PEPPOL-EN16931-R051
All currencyID attributes must have the same value as the invoice currency code (BT-5), except for the invoice total VAT amount in accounting currency (BT-111).
fatal
BR-CL-03
currencyID MUST be coded using ISO code list 4217 alpha-3
fatal