Namespace URIs
RFC 3986 - Uniform Resource Identifier (URI): Generic SyntaxEach URI begins with a scheme name that refers to a specification for assigning identifiers within that scheme.
 Namespaces and versioning
Using XML namespaces to mark the version of XML formats
Namespace Versioning
Major changes in the schema of the namespace would result in a new version of this namespace. So the namespace URI needs to specify a version.
XMLVS
http://www.ibiblio.org/hhalpin/homepage/notes/xvspaper.html

Using Namespace Documents for XML Versioning

/livcos.org/data/map/brainstorm/home