pyfagorass 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.