Do you know what is the XML namespace schema? The URI you show is a namespace URI for the MSBuild project file format, which has nothing to do with the version of MSBuild.
Learn a bit about the schema and the namespace and think by yourself: what would happen if the new namespace would be required each time people upgraded the software?
No, developers are not such idiots. The MSBuild schema provides some provisions for extension, and the namespace is designed to be the save pretty much forever, at least for the time the whole technology of build exists and is being developed. The year you can see in the namespace URI is the year when the schema was released. Why would you think it should become obsolete? And the evolution of the schema and to tools is reflected in the attribute
ToolsVersion
and the elements
ProductVersion
and
SchemaVersion
. See some valid project files to get an idea how it looks.
See also:
http://www.w3.org/TR/xml-names11/#concepts[
^],
http://www.w3schools.com/schema/schema_intro.asp[
^],
http://en.wikipedia.org/wiki/Metadata[
^].
—SA