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Two version numbers describe a Hollerith run, and they move independently.

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The SDK version

The wheel carries a PEP 440 version derived from the release tag. A clean build at tag vX.Y.Z is X.Y.Z; a build with commits after that tag is X.Y.(Z+1).devN, so every install names the commit it came from. One wheel is published per deployment, served from /sdk/. Upgrading is a pip install of a newer URL, and that URL is not interchangeable between deployments.

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The engine version

Every job is stamped with an engine version: eng_ followed by 16 hex characters. It composes the model checkpoint, the container image, the preprocessing pipeline and the wire protocol, so a change to any one of them produces a new value.
A queued job can report eng_pending. The control plane stamps its configured engine when it accepts the job, and the worker that ran it re-stamps the real value on completion, so read the engine version from a terminal job.
  • On a job — engineVersion on the wire, .job.engine_version in the SDK.
  • On an EvaluationResult and on a fitted context, keyed to the engine that produced it.

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What is stable, and what is not

  • Error codes are stable. There are 26, defined once in a shared contract. The build fails if the documented table and the contract disagree, so a code is added rather than renamed or repurposed.
  • Published limits match the contract. The limit values in these docs are checked against the contract file in the same CI job.
  • Model outputs may change. The same table and the same call can return a different prediction under a different engine version. Record the engine version alongside any result you may need to explain later.
Client-side limit checks ship as a snapshot inside the wheel, so a raised server-side limit reaches your code only on the next wheel.

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Deprecation policy

There is no published deprecation policy, no deprecation warning in the SDK, and no support window for older wheels. None of that is defined yet. Until it is, pin the wheel version you tested against and read this page before upgrading.

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Entries

Entries are dated YYYY-MM-DD, newest first, and name the SDK or engine version they apply to when a release is involved.

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2026-08-07 — Documentation replaced

This documentation set replaces the previous one. Three corrections matter, because code written against the old pages may be wrong.
  • Text embeddings are not a Hollerith capability. The previous docs described them as coming. Text columns are ordinal-encoded, and there is no embedding path.
  • Evaluation returns one metric per task — accuracy for classification, RMSE for regression. An earlier example printed an AUC the engine never produces.
  • Scored results are retained for 1 hour, then deleted. The previous docs did not say so.
No SDK or engine release is recorded here yet. Entries begin from this date.

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