KSEF-004
Error Guide
🇵🇱 KSEF-004: Currency code invalid in Poland
ErrorMandatoryNeeds Input
Currency must be a valid ISO 4217 code. Use PLN for domestic invoices.
Quick Facts
Severity
Error (rejection)
Ruleset
KSeF
Mandate
B2B Mandatory
Fix Type
Needs input
Why This Matters in Poland
Poland requires e-invoicing using KSeF XML format. Invoices with this error will be rejected. They cannot be processed for Poland compliance.
Invoice Navigator covers 134 KSeF FA(3) rules for Poland.
How to Fix KSEF-004
Poland E-Invoicing Requirements
Phase
Status
Scope
KSeF voluntary
Live (Jan 2022)
All VAT payers (opt-in)
B2B mandatory — Phase 1
Live (Feb 1, 2026)
Large taxpayers (>200M PLN turnover)
B2B mandatory — Phase 2
Live (Apr 1, 2026)
All remaining VAT-registered entities (SMEs, sole proprietors, VAT-exempt businesses)
B2G
Live (Feb 1, 2026)
Included in general KSeF mandate
Financial penalties
Jan 1, 2027
Up to 100% of VAT amount on non-compliant invoices
Common Causes
- •Invalid currency code format
- •Using currency symbol instead of code
- •Typo in currency code
Fix KSEF-004 automatically
Upload your invoice and let Invoice Navigator auto-remediate this error.