Next.js 16.3 is out: Instant Navigations, lower memory use and faster builds

What's new

• Less memory in dev. According to the team, long next dev sessions use up to 90% less memory.
• Faster builds. Turbopack's disk cache now works for next build and is on by default.
• TypeScript 7 can be used for type checking during the build.
• Faster server rendering: native Node.js streams instead of web streams — up to 22% more requests under load in the team's benchmarks.
• Instant Navigations (behind the cacheComponents and partialPrefetching flags): Partial Prefetching, a new ISR, Instant Insights and the Navigation Inspector in DevTools, a Playwright test helper.
• Root params — access params like [lang] from any Server Component — and catchError for custom error boundaries.

What to watch out for

The memory, build and rendering improvements need no code changes. Instant Navigations are opt-in: the team plans to make this behavior the default in a future major version, so it's worth planning the move to Cache Components early.

How to upgrade

1. Update the packages: npm install next@latest react@latest react-dom@latest, or automatically with the codemod from the upgrade guide.
2. Review experimental flags in next.config and build warnings.
3. Run the build and e2e tests and check key pages before rolling out.

We upgrade Next.js and React projects: we check compatibility, move to the new APIs and roll out without downtime for users.

Source: release announcement on the Next.js blog.