Next.js 13 is the latest version of the popular React-based web framework, which was released in November 2021.

1. Incremental Static Regeneration (ISR): This feature allows Next.js to update static content on a website without requiring a full rebuild, which improves site performance and reduces load times. This is particularly useful for sites with content that updates frequently but doesn't require real-time updates.

2. Automatic Image Optimization: Next.js 13 provides automatic image optimization, which optimizes images based on device size, format, and quality. This helps improve website performance by reducing the size of images and improving load times.

3. Preview Mode: Preview mode allows developers to see what a website will look like before publishing it. This is particularly useful for content editors who want to see how their changes will look on the live site before making them public.

4. Improved Analytics: Next.js 13 provides improved analytics integration, allowing developers to easily track user behaviour and performance metrics. This helps developers optimize their sites and improve the user experience.

5. Improved Security: Next.js 13 includes several security features, including support for Content Security Policy (CSP), which helps prevent cross-site scripting attacks, and stricter XSS filtering by default. This helps improve the security of Next.js sites and reduces the risk of security vulnerabilities.