The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.
SHALL follow the semantic versioning rules as layed out in the Semantic Versioning Specification version 2.0.0 SEMVER.
http://www.ietf.org/rfc/rfc2119.txt