Currency identifier, value must be the same as what is used in tir01-007, DocumentCurrencyCode.

Example value
EUR
Code lists
Currency codes (ISO 4217)
Rules
Identifier/Error message Flag
PEPPOL-T01-R003
An order SHALL be stated in a single currency
fatal
PEPPOL-T01-B25502
Value MUST be part of code list 'Currency codes (ISO 4217)'.
fatal