All notable changes to the AIOSchema specification and reference implementations.

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 v0.5.5 verifiers:

0.1 0.2 0.3 0.3.1 0.4 0.5 0.5.1 0.5.5