The currency in which the monetary amounts in the tax control message is specified relevant to the previous document type

taxcon_Required
Yes
taxcon_Examples
 <taxControlDocument type="Debit" currency="GBP"> 
taxcon_Xpath

/b24Message/taxControl/taxControlDetails/taxControlDocument/@currency

taxcon_Type
Text
taxcon_Sort
8700.00
taxcon_Id
78