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All notable changes to the AIOSchema specification and reference implementations.

v0.5.6 – June 2026

The extension and compliance release. Adds Extension Registry, ai_declaration and compliance official extensions for EU AI Act Article 50, licensed vendor registration, Creator Key Discovery, and a sixth reference implementation (.NET, zero-dependency C#).

Specification

  • Added Extension Registry (§17.5) with licensed vendor registration (§6.1)
  • Added extension size limit: 4KB maximum on extensions object (§6.3)
  • Added ai_declaration official extension: structured AI disclosure (§11.1)
  • Added compliance official extension namespace for jurisdiction-specific regulatory records (§11.2)
  • Added compliance.eu_art50: EU AI Act Article 50(4) editorial exemption record (§11.2.1)
  • Added HTML JSON-LD examples for Level 2 and Level 3 (§11.2.1)
  • Added public_key extension field with normative fingerprint cross-check (§11.3)
  • Added Creator Key Discovery resolution order (§9.5)
  • manifest_signature now covers core + extensions (§5.8)
  • Multi-hash hash_original as array (§5.5)
  • C2PA integration direction clarified (§7.1)
  • Registry governance consolidated (§17.4)
  • JSON Schema updated with compliance namespace (Appendix A)
  • Test vectors TV-01 through TV-24 (TV-19 through TV-24 added in this version)

Reference Implementations

  • Python 3.9+ – 110 / 117 tests, all passing, 18/18 CV vectors
  • TypeScript – 76 tests + 12 cross-check tests, all passing, 18/18 CV vectors
  • Node.js 18+ – 86 tests, all passing, 18/18 CV vectors
  • Go 1.21+ – 26 tests, all passing, 18/18 CV vectors
  • Rust 2021 – 15 tests, all passing, 18/18 CV vectors
  • .NET 8+ – 68 + 14 CV tests, all passing, 18/18 CV vectors (zero external dependencies)

Conformance

  • TV-01 through TV-24 formally defined and implemented across all six suites
  • CV-01 through CV-18 deterministic cross-implementation vectors
  • Bootstrap rule verified across all six implementations: core_fingerprint absent from CORE_HASH_FIELDS
  • All six implementations produce byte-identical output for every vector

v0.5.5 – March 2026

The stable foundation release. First published version of the AIOSchema standard, with five independent reference implementations and a cross-verified conformance test suite.

Specification

  • Renamed hash_schema_block to core_fingerprint throughout – old name accepted as alias for backward compatibility
  • Added Design Philosophy section: Language Neutrality, Universality, Minimalism, Verifiability, Openness
  • Added C2PA interoperability mapping (complementary trust models, not competing)
  • Added RFC 3161 timestamp authority support in anchoring
  • Added manifest_signature field – signs the entire manifest including extensions
  • Added multi-hash support – hash_original may be a string or array of strings
  • Formalized 10-step verification procedure
  • Formalized AnchorResolver callback contract
  • Added previous_version_anchor field for version chain support

Reference Implementations

  • Python 3.9+ – 108 tests, all passing, 14/14 CV vectors
  • TypeScript – 70 tests + 12 cross-check tests, all passing, 14/14 CV vectors
  • Node.js 18+ – 80 tests, all passing, 14/14 CV vectors
  • Go 1.21+ – 27 tests, all passing, 14/14 CV vectors
  • Rust 2021 – 30 tests, all passing, 14/14 CV vectors

Conformance

  • TV-01 through TV-18 formally defined and implemented across all five suites
  • CV-01 through CV-14 deterministic cross-implementation vectors in cross_verify_vectors.json
  • Bootstrap rule verified across all five implementations: core_fingerprint absent from CORE_HASH_FIELDS
  • 26 total checks across 14 CV vectors – all five implementations produce byte-identical output

Supported Versions

The following schema versions are accepted by v0.5.6 verifiers:

0.1 0.2 0.3 0.3.1 0.4 0.5 0.5.1 0.5.5 0.5.6