What Was Signed
On 27 August 2025, the Chancellery of the President announced the signature of the Act of 5 August 2025 amending the VAT Act and the earlier “KSeF Act.” The stated objective is to refine the framework so taxpayers can implement KSeF in accounting systems. In practice, this puts the legal seal on mandatory structured e-Invoicing (KSeF).
Scope and Timing
Universal scope:
The amendment introduces the obligation to issue e-invoices in KSeF for all taxpayers, including both active VAT payers and VAT-exempt entities.
Start date unchanged:
The law adjusts some entry-into-force provisions but does not shift the main KSeF start, which remains 1 February 2026.
2026 Transition Timeline
To ease the first year of the mandate, the law allows limited use of non-KSeF invoices in clearly defined situations:
- 1 February 2026 large taxpayers (2024 turnover > PLN 200 million) Issue structured invoices through the system; receive incoming e-invoices (everyone must be able to receive from this date).
- 1 April 2026 — all other taxpayers move to KSeF.
- 1 January 2027 — smallest/low-volume issuers (those benefiting from the ≤ PLN 10,000/month relief during 2026) must also be fully on KSeF.
- Throughout 2026 (cash registers): invoices issued via cash registers and receipts treated as invoices may continue in electronic or paper form outside KSeF.
Operational Changes you Should Know
- Attachments: KSeF will allow sending attachments as part of the e-invoice, provided the taxpayer registers the intention to issue and send them.
- “Offline24” mode: the act introduces changes governing a new offline pathway for issuing invoices when real-time connectivity is unavailable, with later submission to KSeF.
- Early certificate pick-up: taxpayers can retrieve a KSeF certificate from 1 November 2025 to complete technical onboarding ahead of the mandate.
Entry into Force
The act enters into force the day after promulgation, with specified points taking effect on 1 February 2026. The main KSeF go-live date, 1 February 2026, remains in place.