HTTP 426 Upgrade Required
4xx – Client error
| Status code | 426 |
|---|---|
| Reason phrase | Upgrade Required |
| Class | 4xx – Client error |
| Reference | RFC 9110 |
Frequently asked questions
What does HTTP status 426 mean?
The client must switch to another protocol, e.g. a newer TLS or HTTP version.
Is 426 an error?
Yes, a client error (4xx): the problem lies in the request – for example a wrong URL, missing authentication or invalid data.
Where is HTTP 426 defined?
Status code 426 is specified in RFC 9110.