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HTTP 426 Upgrade Required — What It Means & How to Fix It

Error4xx client error

Overview

The HTTP 426 Upgrade Required status code indicates the server refuses to perform the request using the current protocol and requires the client to upgrade to a different protocol.

Key Details

  • The server must send an Upgrade header indicating which protocol is required.
  • Common when a server requires TLS/HTTPS instead of plain HTTP.
  • The client should switch to the specified protocol and retry.
  • Different from 101 Switching Protocols, which is a successful upgrade.

Common Causes

  • The server requires HTTPS but the request was made over HTTP.
  • The server requires a newer version of the HTTP protocol.
  • An API endpoint requires WebSocket but received a regular HTTP request.

Steps

  1. 1Check the Upgrade header in the response for the required protocol.
  2. 2Switch to HTTPS if the server requires a secure connection.
  3. 3Upgrade your client to support the required protocol version.
  4. 4Update the URL scheme from http:// to https:// if TLS is required.

Tags

httpclient-errorupgradeprotocoltls

Related Items

http-400-bad-requesthttp-401-unauthorizedhttp-402-payment-requiredhttp-403-forbiddenhttp-404-not-found

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Frequently Asked Questions

It means the server requires you to use a different protocol, specified in the Upgrade header. This often means switching to HTTPS or a newer protocol version.