HTTP version 1.1 details eight methods (requests), but is extensible. The described methods are OPTIONS, GET, HEAD, POST, PUT, CONNECT, DELETE, and TRACE. According to the specification, all HTTP servers (web servers) must support the GET and HEAD methods, but all other methods are optional. If the other methods are supported, the support must conform to the specifications listed within the RFC. A head is a request for transfer of header information without transfer of the entire resource. This method is most frequently used for testing purposes and verifying modification and update information.