A comprehensive guide to the breaking changes in Next.js 16 and how to upgrade your existing projects.
Introduction
Next.js 16 brings significant changes including Turbopack as the default bundler, React 19 integration, and a new proxy.ts file replacing middleware.ts for routing. In this guide, we cover all the breaking changes and provide a step-by-step migration path.
Key Changes
The biggest changes include the new revalidateTag API requiring a second argument, the removal of middleware.ts in favor of proxy.ts, and native Turbopack support.