Within four years, Poland reduced its VAT gap by half (2015: 25%, 2019: 11%) due to several legislative and technology measures (digital transactional reporting, online cash registers, real-time early warning system for VAT fraud, incentives for cashless payment). As a next step E-Invoicing will become mandatory. From January 2024 all B2B invoices need to be reported via the National Electronic Invoice system KSeF. The KSeF is a central government platform for invoicing and for receiving invoice