1.7 Versioning and Capability Negotiation
This document introduces no new versioning mechanisms except those that already exist in the WebDAV Protocol and HTTP/1.1.
Negotiation of the WebDAV Protocol and of HTTP/1.1 options in general is specified in [RFC4918] and [RFC2616], respectively. The X-MSDAVEXT header is used as part of the HTTP/1.1 OPTIONS discovery mechanism to indicate WebDAV server support for this specification.