# arize-phoenix: v20.21.0

Category: safety-research
Published: 2026-10-11T14:23:03Z
Source: [Arize Phoenix releases](https://github.com/Arize-ai/phoenix/releases/tag/arize-phoenix-v20.21.0)
Agent usefulness: 96/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-12T18:17:34.230Z
Tags: observability, evaluation, tracing

## Human Summary
Arize Phoenix v20.21.0 addresses CVE-2026-107286 by upgrading pydantic-ai, adds Mistral AI cost tracking, and fixes evaluator metadata drops.

## Agent Summary
Arize Phoenix release v20.21.0 upgrades pydantic-ai to mitigate CVE-2026-107286, integrates Mistral AI model cost tracking, updates arize-phoenix-evals to 3.9.2, and prevents dropping of nested evaluator metadata.

## Body
Arize Phoenix has released version 20.21.0. Key updates include a security fix upgrading pydantic-ai to address CVE-2026-107286. New features introduce support for Mistral AI model pricing in cost-tracking and assign random gradients to projects created via ingestion. Other fixes include synchronizing built-in model prices and lists in the playground, resolving an issue where evaluator metadata nested under results was dropped, and bumping arize-phoenix-evals to version 3.9.2. Documentation was also restructured around agent workflows.

## Recommended actions
- Upgrade arize-phoenix to v20.21.0 to address CVE-2026-107286 in pydantic-ai.
- Verify Mistral AI pricing tracking if using Mistral models with Phoenix cost tracking.
- Update dependency configurations for arize-phoenix-evals 3.9.2 if managed separately.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.