Skip to main content
v2026.11,772 entries · CC-BY 4.0
Dictionary termTrack AStablev2026.2

Model versioning

The practice of identifying a specific revision of an AI model by name, version number, release date, or content hash, sufficient to uniquely distinguish it from earlier or later revisions that may behave differently on the same input.

ByCASRAI Editorial Board
· Last updated 22 Aug 2026
Share this

Ask CASRAI · included with Regulatory Radar

Ask about Model versioning

Ask CASRAI answers research-administration questions and cites the passages behind every claim — and says so when the corpus does not cover something, instead of guessing. It comes with a Regulatory Radar subscription at $29 a month, alongside the daily digest of regulatory changes and the dashboard of what changed.

150 questions a day, on this site, over the API, or inside your own tools through the CASRAI MCP server.

Everything CASRAI publishes — this page, the dictionary, the guides and the news — stays free to read, with no account and no card.

Examples

Worked examples

  • Is an instance

    Reporting 'gpt-4-0613 (OpenAI, accessed 2024-03-15)' rather than just 'GPT-4'

Counter-examples

Looks similar, but isn't

  • Not an instance

    Reporting only 'ChatGPT' without date or version is insufficient for reproducibility

Editorial commentary

Model versioning identifies a specific revision of an AI model precisely enough to distinguish it from earlier or later revisions that may behave differently on the same input — by name, version number, release date, git-style commit hash, or content hash of the weights file itself. It answers “which exact model was this?” rather than “how was this model produced?”.

Why closed-API models make this hard

Open-weight models version cleanly: a downloaded weights file has a fixed hash and never silently changes. Closed, API-served models do not — a provider can update the model served under a stable-sounding name (a “latest” alias, for example) without publishing a new version number, so two calls to the same endpoint months apart may not be running the same model at all. This is a genuine reproducibility problem for research: a result obtained by prompting an API-served model is only reproducible if the exact snapshot used was recorded (a dated snapshot identifier where the vendor offers one, or at minimum the query date, as a fallback).

How this differs from lineage and checkpoints

Versioning is an identification practice, not a provenance record: it labels a revision, it does not describe where that revision came from. Model lineage answers the derivation question; versioning answers the identification question. A checkpoint is an internal training-time artefact that may never receive a public version label at all — versioning is usually reserved for artefacts intended for external release or use.

Practical recommendation

When citing or reporting an AI model’s output in a manuscript or protocol, record the exact version identifier and query date, not just the model family name — the same discipline already required for software and dataset citation.

References

Also known as

Model snapshot · Model release

Machine-readable encodings

Use in your systems

JATS XML <role> element
xml
<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="Model versioning"
      vocab-term-identifier="https://casrai.org/dictionary/term/model-versioning" />
Schema.org DefinedTerm (JSON-LD)
json
{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "@id": "https://casrai.org/dictionary/term/model-versioning",
  "name": "Model versioning",
  "identifier": "https://casrai.org/dictionary/term/model-versioning",
  "description": "The practice of identifying a specific revision of an AI model by name, version number, release date, or content hash, sufficient to uniquely distinguish it from earlier or later revisions that may behave differently on the same input.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/genai-disclosure#set",
  "url": "https://casrai.org/dictionary/term/model-versioning",
  "sameAs": [
    "Model snapshot",
    "Model release"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "publisher": {
    "@id": "https://casrai.org/#organization"
  },
  "author": {
    "@id": "https://casrai.org/#editorial-team"
  },
  "datePublished": "2026-05-21T01:57:42",
  "dateModified": "2026-08-22T15:43:51",
  "inLanguage": "en-GB",
  "isAccessibleForFree": true
}

Referenced across the research world

University of Cambridge logoColumbia University logoCrossref logoUniversity of Edinburgh logoHarvard University logoUniversity of Oxford logoPrinceton University logoStanford School of Medicine logoUniversity College London logoORCID logoUniversity of Cambridge logoColumbia University logoCrossref logoUniversity of Edinburgh logoHarvard University logoUniversity of Oxford logoPrinceton University logoStanford School of Medicine logoUniversity College London logoORCID logo
  • University of Cambridge logo
  • Columbia University logo
  • Crossref logo
  • University of Edinburgh logo
  • Harvard University logo
  • University of Oxford logo
  • Princeton University logo
  • Stanford School of Medicine logo
  • University College London logo
  • ORCID logo

View CASRAI adoption →

Regulatory Radar

Stop finding out after the fact

$29/month, cancel anytime. Daily digest updates from our analysis, a dashboard holding the same items, and a cited assistant for everything they raise.

  • Federal Register, Federal Register+, Grants.gov, Regulations.gov, NSF News, UKRI, plus CASRAI’s own published content.
  • 72,264 indexed passages, and every answer cites the ones it drew on.