Currency identifier, value must be the same as what is used in tir114-007, DocumentCurrencyCode.

Example value
EUR
Code lists
Currency codes (ISO 4217)
Rules
Identifier/Error message Flag
PEPPOL-T114-R003
An order MUST be stated in a single currency
fatal
PEPPOL-T114-B25902
Value MUST be part of code list 'Currency codes (ISO 4217)'.
fatal