HTTP status code 306 is a historical status code that was once used in early drafts of HTTP/1.1 but was ultimately not formally defined as a standard status code. As a result, this status code is not used by servers in actual HTTP communication and does not have a specific meaning.
In the final specification of HTTP/1.1, all 3xx status codes are designated for redirection, while the 306 status code was not assigned any concrete significance. Over time, this status code has come to be regarded as “unused.”
Important Notes
If you encounter status code 306 in documentation or code, it is important to understand that it is not a valid HTTP status code and will not be recognized by any server or client. In practice, you do not need to handle this status code, as it will not appear in standard HTTP responses.
Summary
In summary, the 306 status code is a legacy status code with no practical use and is not utilized in modern HTTP communication.