Last checked and updated on April 18, 2026What Is New in Next.js 6 (summary table)
Next.js 6 delivers a significant upgrade focused on developer experience, performance, and modern React support. The core updates include a major React version bump, built-in CSS pipeline improvements, and a streamlined configuration process.
| Category | Key Changes |
|---|---|
| Core & React | Upgrade to React 16, with support for new context API, fragments, and error boundaries. |
| CSS Support | Built-in CSS and SASS/SCSS support with @zeit/next-css and @zeit/next-sass plugins. |
| Configuration | Introduction of next.config.js for easier, centralized configuration. |
| Performance & DX | Improved error reporting, better hot reloading, and general build performance enhancements. |
| Bug Fixes | Numerous fixes for routing, dynamic imports, and server-side rendering edge cases. |
How does Next.js 6 improve CSS and styling workflows?
The framework now ships with first-class CSS and Sass integration. You no longer need to eject webpack config for basic styling; instead, you install official plugins like @zeit/next-css or @zeit/next-sass and enable them in next.config.js.
In practice, this means you can directly import .css or .scss files into your components or pages. The build process handles bundling and minification automatically, which simplifies setup for teams adopting CSS-in-JS or traditional stylesheets.
What are the implications of upgrading to React 16?
Next.js 6 locks in compatibility with React 16, unlocking its entire feature set for server and client-side rendering. Developers gain access to fragments, portals, improved error handling with error boundaries, and the new context API for state management.
This matters because the new context API provides a cleaner alternative to older state-prop drilling solutions, making it easier to share data across deep component trees without extra libraries. Error boundaries also make applications more resilient by preventing a single component error from crashing the entire page.
Why is the new next.config.js file important?
It centralizes all custom configuration for your Next.js application. Previously, configuring webpack or Babel required more complex overrides. Now, you export a plain JavaScript object from this file to set up plugins, environment variables, and webpack customizations.
This change standardizes project setup. For example, enabling a CSS plugin is now a matter of adding a few lines to this config file, making the build process more transparent and easier to version control across different environments.
FAQ
Is upgrading to Next.js 6 from version 5 straightforward?
Generally, yes. The most common step is updating your package.json and ensuring your React version is compatible. If you use custom webpack config for CSS, you can migrate to the new built-in plugins. Always check the release notes for specific breaking changes related to your project's features.
Do I have to use the new CSS plugins, or can I keep my current setup?
You can keep your current setup, but the new plugins are recommended. They are maintained by the core team and simplify configuration. If you have a complex webpack setup for CSS, evaluate if the official plugins meet your needs before switching.
Can I use React 16.3's new lifecycle methods like getDerivedStateFromProps in Next.js 6?
Absolutely. Next.js 6 supports the entire React 16.x series, so all new lifecycle methods and APIs are available for use in both client and server-rendered components.
How does error reporting improve in this version?
Build errors and runtime errors during development now provide clearer, more actionable stack traces. The overlay for client-side errors is also enhanced, which speeds up debugging by pointing directly to the problematic code in your editor.
Are there any significant breaking changes for existing applications?
A few, mainly around configuration. The introduction of next.config.js changes how you set environment variables and plugins. Also, some internal webpack loaders have been updated, which could affect custom configurations. Review the upgrade guide in the repository for a complete list.