Next.js 15 vs. Next.js 16: What's the Difference?

Next.js 16 marks a pivotal evolution in the framework, transitioning from a simple SSR helper to a comprehensive full-stack React engine, introducing significant changes such as replacing Webpack with Turbopack as the default bundler, which offers substantial performance improvements. The release also brings explicit caching with Cache Components, replacing implicit caching from its predecessor, and introduces proxy.ts to clarify routing and edge logic. Integration with React 19.2 provides stable support for Server Components, Actions, and the React Compiler, enhancing caching, async server APIs, and edge execution. The update results in smoother animations with View Transitions and reduced reliance on custom hooks due to useEffectEvent, improving rendering predictability and reducing boilerplate. While AMP support is fully deprecated, developers are encouraged to transition to Next.js's unified rendering model, leveraging Server Components and Turbopack for performance goals. Migration strategies are outlined for developers looking to upgrade, with considerations for team size, risk tolerance, and the potential need for phased migrations to manage breaking changes and new features effectively.