[standards-jig] Namespace Versioning

Fabrice Desré fabrice.desre at francetelecom.com
Tue Apr 1 08:00:33 UTC 2003

Julian Missig wrote:
> Well, for the most part, newer JEPs have moved to actual URL-style 
> namespaces.
> The major problem with including a version in the namespace is that it 
> offers no indicator of whether or not protocols are compatible anyway.
> I'm a Jabber client, I deal with "jabber:iq:joap:0.3" namespaces. I get 
> a "jabber:iq:joap:0.4" namespace. The only way for me to know that I 
> can try to deal with "jabber:iq:joap:0.4" using my "jabber:iq:joap:0.3" 
> handler is to somehow parse out the version. This brings us into 
> nonstandard usage of namespaces and all sorts of other ickiness I'd 
> rather not get into.

  I agree that including versioning in the namespace URI is of no help 
for a processor, that should not expect a versioning sheme. But it can 
be really useful for debugging purposes and human readibility of the XML 
  I also wonder which namespace you will use when updating a spec if you 
don't want any versionning in the URI. Find a new name for the protocol 
? It looks confusing for me.

> XHTML 1.1 isn't really in support of your argument either. 
> "http://www.w3.org/1999/xhtml" was the namespace identifier for XHTML 
> 1.0. Now XHTML 1.1 comes along, with some slightly incompatible 
> changes, and it still uses the same namespace.

  Indeed, XHTML 1.1 uses the same namespace as XHTML 1.0 because the 
semantic of the elements are the same, which is perfectly right. What is 
different is the DTD. The XHTML 1.1 spec says that (in § 2.1.1) :

4. There must be a DOCTYPE declaration in the document prior to the root 
element. If present, the public identifier included in the DOCTYPE 
declaration must reference the DTD found in Appendix C using its Formal 
Public Identifier. The system identifier may be modified appropriately.

  html PUBLIC "-//W3C//DTD XHTML 1.1//EN"

Note that the public identifier of XHTML 1.1 is different from the 
public identifier of XHTML 1.0.

Fabrice Desré
France Télécom R&D/DTL/TAL
Tél: +(33) (0)2 96 05 31 43
Fax: +(33) (0)2 96 05 39 45

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