Versioning

["Hollenbeck, Scott" <shollenbeck@verisign.com>]

The current EPP object mappings don't include any sort of versioning
information.  Anticipating evolution, it's probably a good idea to have some
sort of versioning mechanism in place.  There are at least two ways it can
be done:

1. Add <version> elements in appropriate places, or

2. Use the namespace- and schema-identifying URIs to identify specific
versions.

Right now I like option 2 better than option 1 because it won't add any
additional elements, and it's more in line with the way XML Schema itself
manages version differences.  As an example, the URI used to identifying the
domain name mapping could be changed from this:

urn:iana:xml:ns:domain

to this:

urn:iana:xml:ns:domain-01

to identify version 1 of the mapping.  If a new version is needed at a later
date, incrementing the version number in the URI provides an easy way to
ensure parser-enforced uniqueness.

Any thoughts or objections?  This type of URI versioning might also be
useful in the base protocol specification, though we currently use a
<version> element there for this purpose.

<Scott/>