React18 Dep Compatibility — Agent Skill by GitHub

From the author

React 18.3.1 and React 19 dependency compatibility matrix.

— the description by SaravananRajaraman

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured reference for managing dependency compatibility during React 18.3.1 and React 19 upgrades. It includes a comprehensive compatibility matrix for common libraries like Apollo Client, Emotion, React Router, and testing utilities, alongside a decision tree for resolving peer dependency conflicts and guidelines for the safe use of --legacy-peer-deps.

What it does

Provides minimum version requirements for React 18.3.1 and 19 compatibility.
Offers a decision tree for resolving npm peer dependency conflicts.
Details specific migration considerations for Apollo Client and React Router.
Defines strict rules for when and how to document the use of --legacy-peer-deps.
Summarizes breaking changes and necessary updates for testing libraries.
Helps assess the scope of complex migrations like React Router v5 to v6.

When to use it

Before initiating a React upgrade to version 18.3.1 or 19.
When encountering npm peer dependency conflicts during package installation.
When deciding whether to defer a major library migration, such as React Router.
When assessing the risk of concurrent mode compatibility issues.
Before accepting a dependency resolution that might require --legacy-peer-deps.

Advantages

Reduces the risk of runtime errors caused by incompatible dependency versions.
Provides a clear, standardized process for handling peer dependency conflicts.
Prevents scope creep by identifying migrations that should be handled in separate sprints.
Ensures consistent documentation practices for legacy dependency workarounds.
Centralizes critical compatibility data for common React ecosystem tools.

Usage examples

“What is the minimum version of @apollo/client required for React 18?”: The skill identifies that @apollo/client 3.8.0 is the minimum version required to support React 18 concurrent mode.
“Should I upgrade React Router to v6 during my React 18 migration?”: The skill advises that React Router v5 to v6 is a major API rewrite and recommends deferring it to a separate sprint unless the project scope is very small.
“How do I handle a peer dependency conflict for a package that doesn't support React 18 yet?”: The skill provides a decision tree to check if the package is critical, search for existing PRs, and only use --legacy-peer-deps as a last resort with proper documentation.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/github/react18-dep-compatibility/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip react18-dep-compatibility.zip -d .agents/skills

Documentation by SaravananRajaraman

React Dependency Compatibility Matrix

Minimum versions required for React 18.3.1 and React 19 compatibility.

Use this skill whenever checking whether a dependency supports a target React version, resolving peer dependency conflicts, deciding whether to upgrade or use legacy-peer-deps, or assessing the risk of a react-router v5 to v6 migration.

Review this matrix before running npm install during a React upgrade and before accepting an npm dependency conflict resolution, especially where concurrent mode compatibility may be affected.

Core Upgrade Targets

Package	React 17 (current)	React 18.3.1 (min)	React 19 (min)	Notes
`react`	17.x	18.3.1	19.0.0	Pin exactly to 18.3.1 for the R18 orchestra
`react-dom`	17.x	18.3.1	19.0.0	Must match react version exactly

Testing Libraries

Package	React 18 Min	React 19 Min	Notes
`@testing-library/react`	14.0.0	16.0.0	RTL 13 uses ReactDOM.render internally - broken in R18
`@testing-library/jest-dom`	6.0.0	6.0.0	v5 works but v6 has React 18 matcher updates
`@testing-library/user-event`	14.0.0	14.0.0	v13 is sync, v14 is async - API change required
`jest`	27.x	27.x	jest 27+ with jsdom 16+ for React 18
`jest-environment-jsdom`	27.x	27.x	Must match jest version

Apollo Client

Package	React 18 Min	React 19 Min	Notes
`@apollo/client`	3.8.0	3.11.0	3.8 adds `useSyncExternalStore` for concurrent mode
`graphql`	15.x	16.x	Apollo 3.8+ peer requires graphql 15 or 16

Read references/apollo-details.md for concurrent mode issues and MockedProvider changes.

Emotion

Package	React 18 Min	React 19 Min	Notes
`@emotion/react`	11.10.0	11.13.0	11.10 adds React 18 concurrent mode support
`@emotion/styled`	11.10.0	11.13.0	Must match @emotion/react version
`@emotion/cache`	11.10.0	11.13.0	If used directly

React Router

Package	React 18 Min	React 19 Min	Notes
`react-router-dom`	v6.0.0	v6.8.0	v5 → v6 is a breaking migration - see details below
`react-router-dom` v5	5.3.4 (workaround)	❌ Not supported	See legacy peer deps note

react-router v5 → v6 is a SEPARATE migration sprint. Read references/router-migration.md.

Redux

Package	React 18 Min	React 19 Min	Notes
`react-redux`	8.0.0	9.0.0	v7 works on R18 legacy root only - breaks on concurrent mode
`redux`	4.x	5.x	Redux itself is framework-agnostic - react-redux version matters
`@reduxjs/toolkit`	1.9.0	2.0.0	RTK 1.9 tested against React 18

Other Common Packages

Package	React 18 Min	React 19 Min	Notes
`react-query` / `@tanstack/react-query`	4.0.0	5.0.0	v3 doesn't support concurrent mode
`react-hook-form`	7.0.0	7.43.0	v6 has concurrent mode issues
`formik`	2.2.9	2.4.0	v2.2.9 patched for React 18
`react-select`	5.0.0	5.8.0	v4 has peer dep conflicts with R18
`react-datepicker`	4.8.0	6.0.0	v4.8+ added React 18 support
`react-dnd`	16.0.0	16.0.0	v15 and below have R18 concurrent mode issues
`prop-types`	any	any	Standalone - unaffected by React version

Conflict Resolution Decision Tree

npm ls shows peer conflict for package X
         │
         ▼
Does package X have a version that supports React 18?
  YES → npm install X@[min-compatible-version]
  NO  ↓
         │
Is the package critical to the app?
  YES → check GitHub issues for React 18 branch/fork
      → check if maintainer has a PR open
      → last resort: --legacy-peer-deps (document why)
  NO  → consider removing the package

--legacy-peer-deps Rules

Only use --legacy-peer-deps when:

The package has no React 18 compatible release
The package is actively maintained (not abandoned)
The conflict is only a peer dep declaration mismatch (not actual API incompatibility)

Document every --legacy-peer-deps usage in a comment at the top of package.json or in a MIGRATION.md file explaining why it was necessary.

Files

ATTRIBUTION.mdAdded by AutoGineer903 B
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md4.4 KiB
references/apollo-details.md2.4 KiB
references/router-migration.md3.4 KiB

LICENSE

MIT License

Copyright GitHub, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Requirements and compatibility

Written for: GitHub Copilot

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs Node.js

Security

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The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download react18-dep-compatibility.zip