This is a summation of the arguments about VersionNo (Versioning) formerly on the EchoExample page. They were moved here to keep that page clear of old discussions.
[AsbjornUlsberg, RefactorOk, DeleteOk] Added the Echo version number (1.0) to the Echo namespace. It's logical that both namespaces, schemas, DTD's and such change with each version of Echo, thus we don't need a "version" attribute. Comments on this are welcome and wanted. I also added an "e"-prefix to the ID's.
[TimBray] I think it would be a big mistake to embed the version number in the namespace name. HTML had a big fight about this, and it's also an issue over at the W3C TAG. The conclusion seems to be that namespace names are for fine-grained identification: "this is HTML", "this is SVG". On the other hand, putting a version="1.0" on the root element would probably be a really good idea.
[AsbjornUlsberg] Well, it's no big deal for me. Let's have a "version" attribute, then. I've added it to the feed element now.
[KenMacLeod] +1. Although I believe that versioning should be in the namespace, there are no standards for making that work well (handling derivation in schemas, and communicating it to applications). When those standards and tools are available, they will have to accomodate all the schemas that have been using version attributes.
[BillDehora] a version element works well in my experience, it's less complicated to associate a version with a document than with a namespace. It'll also work without namespaces, given that using namespaces isn't settled yet.
[SeanPalmer] If you change the meaning/structure of the elements and attributes in a namespace without changing the namespace, then that leads to confusion as to the utility of each of the terms in the namespace. Read RdfAndEcho; if each of the qnames is going to map to a URI, then those URIs must be used consistently. A version attribute or element breaks this. Terms in namespaces should only be updated if: a) you're augmenting, adding optional extensions; or b) you're bugfixing. Data in URIs are bad too, but dates are fine. There's more discussion about this in the #rdfig chatlogs.