React 19 Stable Release: Actions, Server Components, and the New Hooks
React 19 brings official Server Components, Actions for form handling, new hooks like useActionState and useOptimistic, and ref as a prop.
Next.js 15 Stable Release: React 19, Turbopack, and the New Caching Model
Vercel released Next.js 15 with React 19 support, Turbopack Dev now stable, and a completely revamped caching system. fetch requests are no longer cached by default.