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KSEF-BUS-201 SECURITY Error KSeF Guard Only

Unrecommended Unicode characters (W3C XML 1.0)

Niedozwolone znaki Unicode (W3C XML 1.0)

Problem

Invoice contains unrecommended Unicode characters outside the range allowed by W3C XML 1.0 specification. Such characters may cause document processing issues.

How to Fix

Check invoice text fields and remove C1 control characters (U+007F–U+009F) and Unicode non-characters (U+FDD0–U+FDEF, U+FFFE–U+FFFF). Re-export the invoice from your accounting software.

Source Reference

KSeF Guard security guard (W3C XML 1.0 §2.2 Char production; sibling of BUS-163 for multi-byte ranges)

View source

Source Quote

“KSeF rejects invoices containing unrecommended Unicode characters per W3C XML 1.0 §2.2 — C1 control characters (U+007F–U+009F), non-characters (U+FDD0–U+FDEF, U+FFFE–U+FFFF).”
Description SHA-256: f5291d1aedca…

Justification

FORMAT

Legal Basis Chain

1

Allowed characters in XML 1.0

Dozwolone znaki w XML 1.0

“Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]”
W3C XML 1.0 (Fifth Edition), Section 2.2
2

KSeF API v2.4.0 semantic validation

Walidacja semantyczna KSeF API v2.4.0

“KSeF rejects documents containing Unicode characters not recommended by the W3C XML specification.”
KSeF API changelog v2.4.0 (CIRFMF/ksef-docs)