4xx Client error
HTTP 426 Upgrade Required
The server refuses the request using the current protocol but would accept it after the client upgrades to another one, which it names in an Upgrade header.
//_01 Uptime checks
Is 426 up or down for a monitor?
Uptimecheck HTTP monitor
Default settings
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 426 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Is it down? checker
Free, at /is-it-down/
Up. The checker counts any answer below 500 as the site answering: a 426 comes from a server that is running.
//_02 Causes and fixes
Why you see 426 and what to do
Typical causes
- A server that only accepts a newer protocol or a WebSocket connection on that URL.
If you run the site
- Name the required protocol in the Upgrade header and the response body.
If you’re a visitor
- Update your browser or app.
Know the moment your site stops answering as it should
An Uptimecheck monitor requests your page as often as every minute, checks the status code against the ones you expect, confirms a failure with a second check and then alerts you.
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Questions
What does HTTP 426 mean?
The server refuses the request using the current protocol but would accept it after the client upgrades to another one, which it names in an Upgrade header.
Does an uptime monitor count 426 as down?
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 426 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Related status codes
All status codesDowntime is obsolete.
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