Dynamics 365 and KSeF: 5 challenges that can be solved with the Sii Poland’s module 

The National e-Invoicing System (KSeF) in Poland is back in the spotlight, due to the mandatory integration deadline set for February 2026. While this date may still seem distant, many companies must begin preparations now to avoid potential disruptions and fines. Learn about the challenges connected to KSeF implementation process and how to overcome them with Sii Poland’s help. 

KSeF integration with ERP systems is a complex task, full of technical nuances and unclear legal interpretations. Fortunately, Dynamics 365 users, from AX 2012 R3 onwards, can rely on a ready-to-deploy e-invoicing module developed by Sii Poland. It simplifies the implementation process and ensures full compliance with National Tax Administration (KAS) requirements. 

Discover the most common challenges companies face during KSeF implementation – and how Sii Poland helps solve them effectively. 

1. Complex ERP integration with KSeF 

Problem: KSeF doesn’t offer out-of-the-box integration with ERP systems. The Ministry only provides an API – the entire integration process must be handled internally. 

Solution: The Sii Poland module fully manages communication with the KSeF API, eliminating the need to develop custom connections, scripts, or data transfer mechanisms. As a result, your Dynamics 365 system works as if it was natively integrated with the Ministry’s platform. 

2. Errors in structure and format

Problem: KSeF requires invoices to strictly comply with the FA(3) format. Any error or inconsistency may result in the document being deemed rejected by API.  

Solution: The Sii module enables automatic validation of documents before posting and sending. It verifies compliance with the required structure and notifies users of any missing or incorrect elements, helping prevent invoice rejection by KSeF. 

3. Lack of visibility into document status 

Problem: Was the invoice accepted? Did it receive a KSeF number? Was it rejected? Without an integrated system, companies lack real-time insight into their document status. 

Solution: The module provides comprehensive status tracking for each invoice directly within Dynamics 365. From submission to acceptance or rejection – everything is visible and under control. Finance teams can monitor document status in real time.

4. Record keeping and regulatory compliance 

Problem: New regulations introduce changes to archiving obligations. It’s not always clear which documents must be stored, where, or for how long. 

Solution: The module uses Dynamics 365’s built-in mechanisms, fully aligned with KSeF requirements. Additionally, part of the archiving responsibility is handled by KSeF itself. Users have easy access to all e-invoices and confirmations (such as UPO) directly within the system. 

5. Disrupting daily operations 

Problem: New tools can interfere with established accounting processes and cause confusion within finance teams. 

Solution: The module runs within the familiar Dynamics 365 environment, requiring no changes to existing document workflows. It supports multiple invoice types (including corrections, prepayments, and drafts) and can be implemented without disrupting day-to-day operations. 

Ready-to-use solution from a trusted partner 

Sii Poland, a certified Microsoft partner since 2009, developed the KSeF Module for Dynamics 365. Throughout the implementation project, you’ll be supported by experienced ERP consultants and solution architects who know the system inside out. With Sii experts’ help, you gain: 

• Full compliance with current Polish regulations 
• Automated sending and receiving of structured e-invoices 
• High-level security and full alignment with National Tax Administration (KAS) requirements