{"api_version":"1","rule":{"code":"CODE-004","title":"VAT category codes","description":"Line and VAT-breakdown categories must use the EN 16931 subset of UNCL 5305.","severity":"error","ruleset":"code-lists","ruleset_version":"2026.08.3","profiles":["full","simplified"],"effective_from":"2026-08-15","effective_to":null,"source":{"id":"en16931-validation","name":"CEN/TC 434 \u2014 EN 16931 validation artefacts 1.3.16","url":"https://github.com/ConnectingEurope/eInvoicing-EN16931/releases/tag/validation-1.3.16","accessed":"2026-08-15"},"applicability":"See the rule description and selected invoice or technical profile.","remediation":"Add or correct the referenced structured invoice data.","rule_url":"/rules/CODE-004"}}