Advance, final and settlement invoices in KSeF — deadlines, VAT obligation moments and document linking.
An advance invoice confirms receipt of a prepayment. In KSeF it has specific rules and links with the final invoice.
Within 30 days of receiving the advance, no earlier than 60 days before. VAT due arises on the payment date (cash basis for advances).
After delivery you issue a settlement/final invoice reducing the value by earlier advances. It must contain KSeF numbers of all linked advance invoices.
If the contract is terminated or the advance refunded — issue a minus advance correction. VAT correction period — when the buyer received it in KSeF.
Advance invoices are an error-prone area. Danexis tracks all links in wFirma.