Servers MUST support the HTTP GET, HEAD and OPTIONS methods [RFC7231] for clients to read resources or to determine communication options. [Source]
When responding to authorized requests:
-Servers MUST indicate their support for HTTP Methods by responding to HTTP GET and HEAD requests for the target resource with the HTTP Method tokens in the HTTP response header Allow.
Servers MUST indicate supported media types in the HTTP Accept-Patch [RFC5789], Accept-Post [LDP] and Accept-Put [The Accept-Put Response Header] response headers that correspond to acceptable HTTP methods listed in Allow header value in response to HTTP GET and HEAD requests.
When responding to authorized requests, servers MUST indicate supported media types in the HTTP Accept-Patch [RFC5789], Accept-Post [LDP] and Accept-Put [The Accept-Put Response Header] response headers that correspond to acceptable HTTP methods listed in Allow header value in response to HTTP GET and HEAD requests.
Servers MAY include the HTTP Accept-Patch, Accept-Post and Accept-Put headers in the response of a OPTIONS * request.