Upgrade Next.js

Upgrade the current project to the latest Next.js version following official migration guides.

Instructions

1. Detect current version: Read package.json to identify the current Next.js version and related dependencies (React, React DOM, etc.)

2. Fetch the latest upgrade guide: Use WebFetch to get the official upgrade documentation:

   • Codemods: https://nextjs.org/docs/app/guides/upgrading/codemods
   • Version-specific guides (adjust version as needed):
     • https://nextjs.org/docs/app/guides/upgrading/version-16
     • https://nextjs.org/docs/app/guides/upgrading/version-15

3. Determine upgrade path: Based on current version, identify which migration steps apply. For major version jumps, upgrade incrementally (e.g., 13 → 14 → 15 → 16).

4. Prefer the automated path first: the official upgrade codemod bumps deps AND runs the right transforms interactively:

   npx @next/codemod@latest upgrade latest   # or: upgrade patch|minor|major|<version>
   next upgrade                              # built-in self-upgrade command (Next 16.1+)
   

   Fall back to individual codemods when the automated path can't run:

   npx @next/codemod@latest <transform> <path>
   

   Common transforms:

   • next-async-request-api - Updates async Request APIs (v15)
   • next-request-geo-ip - Migrates geo/ip properties (v15)
   • next-dynamic-access-named-export - Transforms dynamic imports (v15)
   • remove-experimental-ppr / remove-unstable-prefix - PPR & unstable_* cleanup (v16)
   • middleware-to-proxy - middleware.ts → proxy.ts (v16)
   • next-lint-to-eslint-cli - migrate off next lint (v16)

5. Update dependencies: Upgrade Next.js and peer dependencies together:

   npm install next@latest react@latest react-dom@latest
   

6. Review breaking changes: Check the upgrade guide for manual changes needed:

   • API changes (e.g., async params in v15)
   • Configuration changes in next.config.js
   • Deprecated features being removed

7. Update TypeScript types (if applicable):

   npm install @types/react@latest @types/react-dom@latest
   

8. Test the upgrade:

   • ASK the user before running npm run build (builds are slow; some users forbid unprompted builds)
   • Run npm run dev and test key functionality