Next.js 15 New Features and Upgrade Guide: Migrating Your Project

Wed, 08 Jul 2026 10:00:00 +0900

Next.js 15 is officially released, built on React 19 stable. This major update brings a stable Partial Prerendering (PPR) system, a revamped caching strategy, and Turbopack integration for development builds.

This article walks through the key new features and provides a step-by-step upgrade guide for migrating from Next.js 14.

1. Key New Features

Native React 19 Support

Next.js 15 fully embraces React 19. Server Components are now stable, and new hooks like use() and useOptimistic() work directly within the App Router. Server Actions are also more efficient with improved performance for action-oriented hooks.

Key Points for Performance Optimization in Next.js App Router

Wed, 25 Feb 2026 12:00:00 +0900

Leveraging React 18 capabilities, Next.js App Router provides a highly performant architecture for building modern web frontends.

However, misconfiguring server-client boundaries or caching rules can lead to slow response times. In this guide, we explore practical optimization techniques to build blazing-fast Next.js applications.

1. Maximize React Server Components (RSC)

The primary benefit of the App Router is that all components are Server Components by default. This eliminates large portions of JavaScript from the client-side bundle.

React on Kaisekukun

Next.js 15 New Features and Upgrade Guide: Migrating Your Project

1. Key New Features

Native React 19 Support

Key Points for Performance Optimization in Next.js App Router

1. Maximize React Server Components (RSC)