CII-DT-031

[JoergWaltherOdette]

Current wording: currencyID should not be present.
This check raises a fatal error. To be consistent, the wording should then be:
Attribute currenyID must not be used.

However, I think for the sake of consisteny the currencyID for amount should be allowed as optional attribute and the checked when present, if the value matches the invoice currency or, for tax totals, the different tax currency, if such a different tax currency has been specified.

Reason:
In UBL the currency attribute is required and must be specified for each amount. So it would make sense to at least allow it for CII instances as well.