# MIDDLEWARE_RUNTIME_DEPRECATED

The `MIDDLEWARE_RUNTIME_DEPRECATED` error occurs when a middleware is using a deprecated runtime. This error can occur when a middleware is using a runtime that is no longer supported by the platform.

## Troubleshoot

To troubleshoot this error, follow these steps:

1. **Identify the affected project:** Use [Vercel Logs](/docs/observability/runtime-logs) to identify if your project is experiencing this error. Look for the `MIDDLEWARE_RUNTIME_DEPRECATED` error in your project's runtime logs.
2. **Locate the middleware:** Once you've identified the project, check if it has a `middleware.js` or `middleware.ts` file in the root directory or uses Routing Middleware in any way.
3. **Redeploy the project:** Redeploy the project to automatically upgrade to the latest supported runtime version. However, if the redeploy fails, you may need to:
   - **Update your Node.js version:** Check your project's Node.js version setting in the Vercel dashboard or `package.json` and update it to a [supported version](/docs/functions/runtimes/node-js#node.js-version)
   - **Update dependencies:** Outdated dependencies may not be compatible with newer Node.js versions. Update your `package.json` dependencies to their latest compatible versions before redeploying


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title: "NOT_FOUND"
description: "The requested resource was not found. This is a deployment error."
last_updated: "2026-02-03T02:58:42.104Z"
source: "https://vercel.com/docs/errors/NOT_FOUND"
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