Italy's Agenzia delle Entrate published technical specification 1.9 on 31 January 2025, in force from 1 April 2025. Two additions matter to anyone checking invoice files before they go to the SdI exchange:
- TD29, a document type a buyer uses to report a supplier's omitted or irregular invoicing (art. 6(8), D.Lgs. 471/97). It replaces the old habit of issuing a TD20 self-invoice for that case.
- RF20, the seller's tax regime for the EU cross-border VAT franchise for small businesses (Directive 2020/285).
einvoice-preflight flagged both as unknown codes until today. It now accepts them, and adds one rule, IT-023: a TD29 whose seller is not Italian (IdPaese other than IT), which SdI rejects with error 00473.
What this rests on. Press and vendor summaries of the specification, not the Agenzia's own text, which the build host cannot reach. The README and the flagship ledger say so, and the next step is to check the codes against the primary document and a real SdI file.
Try it: paste a FatturaPA file into the checker; nothing leaves your browser.