BR-DE-21: specification identifier (BT-24) is not the XRechnung id

Put the identifier of the current XRechnung version into CustomizationID, that is urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0 for the CIUS. With the extension it reads urn:cen.eu:en16931:2017#conformant#urn:xeinkauf.de:kosit:extension:xrechnung_3.0, without any spaces.

<ubl:Invoice>
  <cbc:CustomizationID>urn:cen.eu:en16931:2017</cbc:CustomizationID>
  <cbc:ProfileID>urn:fdc:peppol.eu:2017:poacc:billing:01:1.0</cbc:ProfileID>
</ubl:Invoice>

<ubl:Invoice>
  <cbc:CustomizationID>urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0</cbc:CustomizationID>
  <cbc:ProfileID>urn:fdc:peppol.eu:2017:poacc:billing:01:1.0</cbc:ProfileID>
</ubl:Invoice>

The specification identifier of the invoice is not the current identifier of the XRechnung standard. This identifier tells the recipient which rules the invoice was built for; invoice portals choose their checks by it. With a deviating identifier the invoice may not be recognised as an XRechnung and may be checked against the wrong rules.

• The invoicing software still writes the identifier of an older XRechnung version, for example 2.3 instead of 3.0.
• Only the EN 16931 identifier urn:cen.eu:en16931:2017 was entered, without the XRechnung suffix.
• A typo or a variant spelling of the identifier, such as a space or upper-case letters.