Version Numbers
The fundamental problem with a version # in a document is that it doesn’t provide for a given document to be valid under more than one version. What we really need is to be able to indicate a “space of versions” that a given document is valid under, whether that’s a list or regexp or whatever.
Dave’s writing on versioning is great; I hope he’ll turn it into a book one day.
If by “version number” you mean that a document follows a certain schema, you get jclark’s latest post: “Validity should be treated not as a property of a document but as a relationship between a document and a schema.”
http://blog.jclark.com/2007/04/validation-not-necessarily-harmful.html
PS: “lbruno(Luis )@(Bruno)100blossoms.com” is a valid email address
True: /blog/st/2007/04/11/james_clark_on_validation.html