Is Your Company Ready for KSeF 2.0?
The National e-Invoicing System (KSeF) is one of the most significant changes in the digitalization of tax processes in Poland. The upcoming version, KSeF 2.0, and the mandatory e-invoicing starting in 2026 will introduce major changes for both large enterprises and smaller businesses. For many companies using ERP systems—especially SAP—the upcoming deadlines mean not only adapting accounting processes but also planning technological integration. An improper implementation approach may result in document workflow disruptions, risk of penalties, or VAT settlement issues.
This article presents the latest updates on KSeF 2.0, the implementation timeline, and key challenges related to ERP system integration—with a focus on SAP. You’ll learn what to watch out for when planning implementation and how to avoid common integration issues.
Key KSeF 2.0 Implementation Dates – What You Need to Know
Phases of Mandatory KSeF Implementation
According to the latest plans from the Ministry of Finance, the mandatory use of KSeF 2.0 will be rolled out in two main phases:
- Phase I – from February 1, 2026 – for companies with sales exceeding PLN 200 million (including VAT) in 2024.
- Phase II – from April 1, 2026 – for all other businesses.
A major change for taxpayers is that the sales threshold will be based on 2024 data, allowing companies to assess early on which deadline applies to them.
Key Events Schedule
| Date | Event |
|---|---|
| June 2025 | Publication of FA(3) logical structure on ePUAP |
| June 2025 | Publication of KSeF 2.0 API documentation |
| September 2025 | Launch of open API testing for KSeF 2.0 |
| November 2025 | Production certificates become available |
| November 2025 | Taxpayer Application test version released |
| February 2026 | Start of mandatory KSeF 2.0 – Phase I |
| April 2026 | Start of mandatory KSeF 2.0 – Phase II |
What’s New in KSeF 2.0?
1. The most important changes and new functionalities in KSeF 2.0
1.1 Offline24 Mode – Invoicing Outside KSeF, But Still Compliant
A key new feature is the Offline24 mode, which allows issuing invoices outside the KSeF system using a QR code. These invoices must be entered into KSeF no later than the next working day. This solution:
- Minimizes the risk of invoicing bottlenecks.
- Protects against system errors or KSeF downtime.
- Is especially important for businesses working with consumers, foreign entities, or in a B2C model.
1.2 Ability to Add Attachments to Invoices
The FA(3) structure allows attachments to invoices (e.g., utility bills, telecom services, or consolidated documents). The “Zalacznik” node in FA(3) lets businesses include detailed data (e.g., itemized billing, delivery tables), meeting the needs of those issuing collective invoices.
For more information on the FA(3) rules, see our article: Latest changes to KSeF – new logical structure of FA(3)
1.3 Early Generation of Issuer Certificates
Starting in November 2025, production certificates necessary for invoice authorization in KSeF can be generated. These certificates enable:
- Secure invoicing in online, offline, and Offline24 modes.
- Continuity of invoicing even during system outages.
1.4 KSeF 2.0 Test Environment – Preparation Before Launch
The Ministry of Finance plans to release a test environment for KSeF 2.0’s API with mandatory functions in September 2025. This will allow integrators and businesses to:
- Verify the correctness of transmitted data.
- Test ERP systems integration, including SAP.
- Prevent issues in the production environment.
1.5 QR Code Standardization for Online and Offline Invoices
A unified QR code structure has been introduced for both online and offline invoices. The new rules:
- Enable verification of whether an invoice was issued by an authorized taxpayer.
- Increase data security and integrity.
- Simplify the authenticity verification process.
1.6 Unified Postponement Date – End of 2026
Certain obligations have been postponed and unified to come into force on December 31, 2026, including:
- Including the KSeF number in transfers between active VAT taxpayers.
- Issuing invoices from cash registers and receipts with tax ID (NIP) as invoices.
- Low-value transactions (up to PLN 450 or PLN 10,000 monthly).
- Imposing penalties for not using KSeF.
This eliminates the risk of ambiguity related to the phased implementation of the regulations.
1.7 Deferred Obligation for Flat-Rate Farmers
The new deadline for VAT_RR invoices and corrections is April 1, 2026 (previously February 1, 2026), giving farmers more time to adapt to KSeF requirements.
Read our article: Latest changes regarding KSeF – new logical structure of FA(3)
Integration Challenges of KSeF 2.0 with SAP – Key Technical Considerations
Integrating SAP with KSeF requires a precise approach, particularly in communicating with the KSeF API and handling the FA(3) structure. Key challenges for implementation teams include:
1. Data Mapping and Document Format Adjustment
SAP generates invoices in formats like IDoc or PDF by default. KSeF requires XML files based on the FA(3) structure. Proper mapping of SAP fields to this structure is essential.
Recommendations:
- Create dedicated integration interfaces.
- Verify the accuracy of source data (e.g., tax ID, invoice date).
2. Handling KSeF Communication Statuses
SAP should support the full invoice lifecycle:
- Sending to KSeF.
- Receiving the KSeF number.
- Handling error messages (e.g., document rejection).
- Monitoring deadlines for Offline24 mode.
3. Security and Digital Signatures
Certificates are required to authorize invoice submission. Ensure secure certificate management within SAP and integrate digital signing with automation processes (e.g., SAP PI/PO, SAP CPI).
4. KSeF 2.0 API Integration Testing
With the test environment becoming available in Q3 2025, full integration testing is recommended:
- Simulate invoice sending and receiving.
- Validate FA(3) compliance.
- Test failure scenarios (Offline24 mode).
Risks of Not Being Ready for Integration
- Invoicing delays.
- Potential fines for non-compliance.
- Auditability issues.
- Disruptions in document flow between SAP and external systems.
Summary: KSeF 2.0 as a Process Optimization Opportunity
While KSeF 2.0 implementation requires substantial involvement from IT, accounting, and compliance teams, proper integration can drive automation and process organization. The key is thorough preparation – technically and organizationally.
Take advantage of our experience – let’s work together!
The Haergi team has extensive experience in integrating SAP with KSeF and implementing e-invoicing solutions in complex organizations. We offer:
- Comprehensive ERP readiness audits.
- Designing and deploying integration interfaces between SAP and KSeF.
- Full testing and post-implementation support.
Contact us to learn how we can support your company in implementing KSeF 2.0 and integrating it with SAP. Secure a safe, legally compliant, and efficient KSeF implementation.
