The SvelteKit has undergone significant changes, including a new routing system, layout overhaul, and a switch to the Vite CLI. The old file-based routing system has been replaced with directory-based routing, requiring a + prefix to generate routes. This change aims to improve code organization and reduce confusion. Additionally, the load function has moved from .svelte files to endpoint files, allowing for more flexibility in data loading. The exports that dictate page behavior have also changed, and SvelteKit is now a Vite project with a vite.config.js file. A migration guide and command, npx svelte-migrate routes, are available to help users navigate these changes. To migrate, users need to remove old lock files and node_modules, update dependencies, run the migration command, update props in +page.svelte files, remove <script context="module"> tags, and ensure scripts have been updated to the Vite CLI.