KSeF 2.0: what changed and what to do with KSeF 1.0 setups
Choose what you still have from the previous system version. The tool shows the date until which it works and the next step.
Deadline
31 December 2026
Old tokens work until the end of 2026 (section 13 of the regulation); then a KSeF certificate or a new token.
| What to do | generate a token or certificate in KSeF 2.0 |
| Invoice structure | FA (3), version 1-0E |
| KAS helpline | 22 330 03 30 |
Sources: regulations 2025 item 1815 and 2026 item 169; Finance Ministry notices on the KSeF 2.0 environments.
Prepared by Radif Partners · Method · VAT Act, regulations and ministry notices checked on 25 October 2026
KSeF 2.0 is the version of Poland's National e-Invoicing System that has run in production since 1 February 2026, together with the mandate. It replaced the earlier, voluntary version and changed almost everything invoicing software deals with: a new API 2.0 with different authentication and sessions, a single invoice structure FA (3) instead of FA(2), KSeF certificates available since 1 November 2025, QR codes on invoices handed over outside the system, and the offline24, unavailability and failure modes. The test environment of the new version opened on 30 September 2025, and the demo of the Taxpayer Application on 15 November 2025. Three dates matter most to users: old tokens generated in KSeF 1.0 work until 31 December 2026 under section 13 of the regulation on using KSeF, the old trusted-profile login ended on 13 February 2026, and FA(2) files are no longer accepted in production.
What changed between versions
| Area | KSeF 1.0 | KSeF 2.0 |
|---|---|---|
| status | voluntary | mandatory from 1 February 2026 |
| invoice structure | FA(2) | FA (3), version 1-0E |
| interface | API 1.0 | API 2.0, new sessions and authentication |
| login | token, signature, trusted profile | KSeF certificate, token, signature, national login node |
| invoice outside the system | no code | QR code, two in offline mode |
| special modes | failure | offline24, unavailability, failure, total failure |
The ministry describes the version on its KSeF 2.0 general information page, and the technical details are in the API documentation.
The transition calendar
| Date | Event |
|---|---|
| 1 September 2025 | KSeF 1.0 test environment switched off |
| 30 September 2025 | API 2.0 test environment |
| 1 November 2025 | certificates and permissions module |
| 3 November 2025 | Taxpayer Application in the test environment |
| 15 November 2025 | demo environment |
| 1 February 2026 | KSeF 2.0 production and the mandate |
| 13 February 2026 | end of the old trusted-profile login |
| 31 December 2026 | end of KSeF 1.0 tokens |
Environment dates come from the ministry notices on the switch of test environments and the demo environment; login deadlines from regulation 2025 item 1815 and its 2026 amendment.
Check your business
The most common leftover from the old version is a token stored in software. Who logs in and with what can be checked here:
You log in with
You log in with
Trusted profile or e-ID (national node), qualified signature
| ZAW-FA notification | no |
| Tokens generated in KSeF 1.0 | work until 31 December 2026 |
| KSeF certificate available | since 1 November 2025 |
More on tokens and certificates: token and permissions. Practise the new version in the test environment, and open FA (3) files in the invoice reader.
What the new version changes for users without software
Someone who issues a few invoices a month in the free Taxpayer Application will mainly notice the new login method and a new form layout following the FA(3) structure. Invoices handed to customers outside the system get a QR code, and when there is no connection the application lets you issue an invoice in offline mode. The archive of invoices from the voluntary period has been kept.
What changes for businesses with their own software
Software connecting to KSeF through the API must move to the new authentication, new sending sessions and a new response format. It must also compute the SHA-256 hash of the file and create QR codes, and in offline mode sign the second code with a certificate. The ministry’s technical documentation and libraries are public. If your software was built only for version 1.0, ask the vendor to confirm that it supports version 2.0 and FA(3).
Accounting firms should review the permissions clients granted in the previous version of the system and request new ones where needed, because version 1.0 tokens stop working at the end of 2026.
If you do not know which version your software uses, check the structure of an invoice file it produced: a header with the code FA (3) means the new version, FA (2) the old one. You can open the file in the reader on this site, which recognises the structure at once and tells you whether it is supported.