When I set package.json engines section as:

  "engines": {
    "node": "18.x" 
  }

Vercel deploy logs show:

Error: Node.js Version "18.x" is discontinued and must be upgraded. Please set "engines": { "node": "24.x" } in your `package.json` file to use Node.js 24. Learn More: http://vercel.link/node-version

When I set it to:

  "engines": {
    "node": "24.x" 
  }

The logs show:

error during build:
Error: Unsupported Node.js version: v24.11.1. Please use Node 16 or Node 18 to build your project, or explicitly specify a runtime in your adapter configuration.
    at get_default_runtime (file:///vercel/path0/node_modules/@sveltejs/adapter-vercel/index.js:17:8)
    at adapt (file:///vercel/path0/node_modules/@sveltejs/adapter-vercel/index.js:157:67)
    at adapt (file:///vercel/path0/node_modules/@sveltejs/kit/src/core/adapt/index.js:26:8)
    at finalise (file:///vercel/path0/node_modules/@sveltejs/kit/src/exports/vite/index.js:808:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)
    at async Object.handler (file:///vercel/path0/node_modules/@sveltejs/kit/src/exports/vite/index.js:830:5)
    at async PluginDriver.hookParallel (file:///vercel/path0/node_modules/rollup/dist/es/shared/node-entry.js:25254:17)
    at async Object.close (file:///vercel/path0/node_modules/rollup/dist/es/shared/node-entry.js:26506:13)
    at async build (file:///vercel/path0/node_modules/vite/dist/node/chunks/dep-8609dc5d.js:47909:13)
    at async CAC. (file:///vercel/path0/node_modules/vite/dist/node/cli.js:822:9)
Error: Command "vite build && npm run update-version" exited with 1

svelte.config.js looks like this:

import adapter from "@sveltejs/adapter-vercel";
import { vitePreprocess } from "@sveltejs/kit/vite";

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    // adapter-auto only supports some environments, see https://kit.svelte.dev/docs/adapter-auto for a list.
    // If your environment is not supported or you settled on a specific environment, switch out the adapter.
    // See https://kit.svelte.dev/docs/adapters for more information about adapters.
    adapter: adapter(),
  },
  preprocess: [vitePreprocess({})],
};

export default config;