- A structured invoice in KSeF is an XML file, so a visual version is created only to make it readable for people.
- The visualized invoice is not a separate invoice and does not replace the invoice stored in KSeF.
- In the described case, the invoice was issued on 8 May 2026, when it was sent to KSeF and received its KSeF number.
- The fact that the visual version was sent to the buyer later (10 May 2026) does not change the invoice issue date.
- Therefore, the date of issue is 8 May 2026.
Source: prawo.pl
Note that this post was (partially) written with the help of AI. It is always useful to review the original source material, and where needed to obtain (local) advice from a specialist.
