Hello,
Thank you for your question.
If you have not locked your accounting period in Enterprise for the previous fiscal year, you can still make a Credit Note for the invoice and make it update the stock.
If you have already locked your accounting for the previous fiscal year, you will have to make a manual transaction and add a note as to why it was necessary (i.e. dealing with a duplicate invoice for a customer in the previous fiscal year).
Regards,
HansaWorld Support