Next.js 16.1 brings Turbopack file system caching to development mode by default, delivering up to 14× faster compile times when restarting the dev server. The release includes an experimental bundle analyzer for optimizing production bundles, simplified debugging with `next dev --inspect`, and improved handling of transitive external dependencies. Additional improvements include 20MB smaller installs, a new `next upgrade` command, and better async import bundling in Turbopack.