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Updating Protocols to Avoid 426 Update Required Errors - HTTP Error Code 426

Anchal Rastogi
~ 6 min read | Published on Mar 28, 2024


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What is a 426 Error?

HTTP status code 426, "Update Required," indicates that the client should switch to a different protocol, as the current one is no longer supported by the server. It's a client error response code, signaling that the user's browser needs to update its protocols to continue communication with the server.

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What Are the Possible Causes for 426 Error?

  1. Outdated Protocol Version: One common cause is when the client's protocol version is outdated and no longer supported by the server.
  2. Server Configuration Changes: The server might have undergone updates or configuration changes that require clients to use newer protocols.
  3. Misconfigured Proxy Servers: If there are proxy servers involved, misconfigurations in these servers can lead to 426 errors.

How to Handle 426 in JavaScript

When encountering a 426 error in JavaScript, developers can handle it gracefully by detecting the error status code and guiding users to update their protocols. Below is a basic example of handling a 426 error in JavaScript:

  .then(response => {
    if (response.status === 426) {
      // Redirect or display a message to the user indicating the need for protocol update
      alert('Update required: Please update your browser or protocol.');
    } else {
      // Handle other response codes
  .catch(error => console.error('Error:', error));

Best Practices for Using 426 Status Code

  1. Clear Communication: Provide clear instructions or messages to users when they encounter a 426 error, guiding them on how to proceed with the required updates.
  2. Utilize Upgrade Header: Servers should include an "Upgrade" header in the response, specifying the required protocol version for clients to switch to.
  3. Implement Redirection: If feasible, automatically redirect users to resources where they can update their protocols or download the necessary updates.

How to Test 426 Status Code on Postman

Testing a 426 status code on Postman involves simulating a request where the server responds with the said status code. Follow these steps:

  1. Open Postman: Launch the Postman application.
  2. Create a Request: Set up a request to the server that you want to test.
  3. Send Request: Send the request to the server.
  4. Inspect Response: Check the response received. If it includes a 426 status code, your test is successful.

How to Test 426 Status Code in DevTools Browser in Chrome

Testing a 426 status code in DevTools Browser in Chrome can be done by using the Network tab to inspect the response of a request. Here's how:

  1. Open DevTools: Open Chrome DevTools by pressing F12 or right-clicking on the page and selecting "Inspect."
  2. Go to the Network Tab: Navigate to the "Network" tab within DevTools.
  3. Send Request: Trigger the request you want to test (e.g., by refreshing the page or making an AJAX request).
  4. Inspect Response: Look for the request in the network log. If the response includes a 426 status code, it means the test was successful.

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Frequently Asked Questions

Q: How can I prevent encountering 426 errors on my website?

A: To avoid 426 errors, ensure that your website's protocols are up-to-date and compatible with the server's requirements. Regularly check for updates and follow best practices for protocol maintenance.

Q: Is a 426 error the same as a 404 error?

A: No, a 426 error signifies that the client's protocols need updating, while a 404 error indicates that the requested resource was not found on the server.

Q: Can a 426 error be fixed by clearing browser cache?

A: Clearing the browser cache won't typically resolve a 426 error. It's usually related to protocol versions and requires updating the client's software.

Q: What should I do if I encounter a 426 error on a website?

A: Follow any instructions provided by the website to update your protocols. If none are available, consider contacting the website's support for assistance.

Q: How do I know which protocol version to update to when facing a 426 error?

A: The server should provide guidance in the response, often through the "Upgrade" header, indicating the required protocol version.


In conclusion, encountering a 426 "Update Required" error can be an indication that your browser's protocols need updating to continue accessing certain websites or services. By understanding the causes and best practices for handling this error, developers can ensure smoother user experiences. Zipy's tool offers valuable assistance in monitoring and managing such errors, providing session replay capabilities for effective troubleshooting. Explore Zipy's capabilities here to enhance your error-handling strategies.

Read more resources on 4xx error status codes

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