Evidently pydantic 2 support landed in 0.4.16, pyarrow pin removed

TL;DR

Upgrade to 0.4.16 or later for pydantic 2. For pydantic 2 with Evidently, upgrade to 0.4.16 or later; older releases are pinned to pydantic 1 by the FastAPI-based UI service.

Steps

1. For pydantic 2 with Evidently, upgrade to 0.4.16 or later; older releases are pinned to pydantic 1 by the FastAPI-based UI service. The pyarrow pin is gone too (replaced by pandas[parquet]), so let pandas choose the pyarrow version.

When to use

You are seeing this: Pydantic v2 support landed in Evidently 0.4.16; earlier the UI service's FastAPI dependency blocked the bump. Use this skill when you run into "Evidently pydantic 2 support landed in 0.4.16, pyarrow pin removed".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: 0.4.16. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Evidently issue #862 (closed): users needed pydantic v2 and newer pyarrow. Maintainers mike0sv and emeli-dral explained the constraints: the pyarrow dependency was removed in #885 and replaced with pandas[parquet], so any pyarrow version pandas accepts works. Pydantic v2 support landed in Evidently 0.4.16; earlier the UI service's FastAPI dependency blocked the bump. Upgrade to 0.4.16 or later for pydantic 2.

Verified resolution: For pydantic 2 with Evidently, upgrade to 0.4.16 or later; older releases are pinned to pydantic 1 by the FastAPI-based UI service. The pyarrow pin is gone too (replaced by pandas[parquet]), so let pandas choose the pyarrow version.

Source URL: https://github.com/evidentlyai/evidently/issues/862