Dependency upgrade intelligence

See the risk before the diff becomes an incident.

Start with a verified, compute-free report. Then create an account and run the same evidence-linked pipeline on your own dependency upgrade.

Verified demo analysis

react 18.2.0 19.1.0

NPM · trace demo-react-1…

New comparison

Upgrade verdict

High-risk upgrade

The 19.1 step is smaller, but server component consumers should align their framework and bundler before deployment.

Risk score
86
Confidence
high
Evidence
complete

Security radar

2 known advisories affect the target

Current18.2.0
Target19.1.0
Analysis tokens
2,778
Estimated generation cost
Included / cached

Token totals describe the generated analysis artifact. Cache hits do not repeat LLM spend.

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Evidence map

What changes across this upgrade

Counts are calculated from the actual entries rendered below.

Breaking changes

2

  1. Legacy root API removed

    Applications must replace ReactDOM.render with createRoot.

    Introduced in 19.0.0

  2. Ref callback cleanup semantics

    Ref callbacks may return cleanup functions; implicit returns can now conflict with type expectations.

    Introduced in 19.0.0

Security fixes

1

  1. Server component protocol hardening

    Upgrade patched server component serialization behavior and review framework advisories.

    Introduced in 19.0.0

Features

3

  1. Actions and optimistic state

    New action primitives coordinate pending state, errors, and optimistic updates.

    Introduced in 19.0.0

  2. Document metadata support

    Metadata tags can be rendered directly from components.

    Introduced in 19.0.0

  3. Owner stack diagnostics

    Development diagnostics can provide a component owner stack.

    Introduced in 19.1.0

Deprecations

1

  1. Element ref access

    Accessing element.ref is deprecated; use element.props.ref.

    Introduced in 19.0.0

Fixes

2

  1. Hydration diagnostics

    Hydration mismatch reporting is consolidated and more actionable.

    Introduced in 19.0.0

  2. Suspense stability

    Several Suspense and hydration edge cases were corrected.

    Introduced in 19.1.0

Other

0

No items detected.

Release path

Version timeline

Up to the latest 50 deterministic slice milestones.

  1. 18.2.0 → 19.0.0complete

    React 19 changes rendering and form action behavior. Audit legacy root creation, ref callbacks, and server/client boundaries before rollout.

    Dec 5, 2025 · e3-llm
  2. 19.0.0 → 19.1.0complete

    The 19.1 step is smaller, but server component consumers should align their framework and bundler before deployment.

    Mar 28, 2026 · e3-llm

Action plan

Before you merge

  1. Replace legacy root creation

    Migrate every ReactDOM.render and hydrate call, then exercise unmount paths in integration tests.

  2. Align the framework release

    Use a framework version that explicitly supports the React 19 server component protocol.

  3. Ship through a canary

    Start with a small traffic cohort and watch hydration, form submission, and error-boundary telemetry.

Local preview

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How to read this report

Facts first, narrative second.

VersionDiff keeps evidence-linked facts separate from optional narrative synthesis. Risk overrides remain deterministic, security-data failures remain visible, and cached analysis never pretends to be a fresh provider charge.