To allow RDF parsers to error or warn about unsupported RDF versions as early as possible, + RDF serialization formats are expected to allow a version to be specified, + via either a media-type parameter, + a version announcement in a format-specific syntax, + or both.
+ +When the version is indicated both in a media-type parameter and in syntax, + they are expected to be the same. + If they differ, + parsers use the version from the media-type parameter and might emit a warning about the mismatch.
+ +To retain compability that is as broad as possible with older parsers, + only RDF documents that make use of RDF 1.2-specific functionality + are encouraged to announce their version (i.e., for RDF documents that do not make use + of RDF 1.2-specific functionality it is discouraged to announce a version).
+ +To announce the version in the HTTP responses using the Content-Type header,
+ the version parameter is expected to be used,
+ as illustrated in the following example response.
HTTP/1.1 200 OK +Content-Type: text/turtle; version=1.2 +Location: http://example.com/document.ttl ++ +
When requesting an RDF document from an HTTP server, the version parameter
+ can be used during content negotiation [[WEBARCH]]
+ by including it in the Accept request header,
+ as illustrated in the following example request.
GET /document.ttl HTTP/1.1 +Host: example.com +Accept: text/turtle; version=1.2 ++