OpenTravel Alliance Revised Namespace and Versioning Specification

Identify a set of Namespace & Versioning goals that satisfy both OTA’s Best Practices and any new OTA agreed namespace and versioning requirements that also maps well with existing technology standards, guidelines and implementations. The intent is to provide clear and consistent best practices that can help simplify OTA’s task for managing XML content for the Travel Industry.

http://www.opentravel.org/downloads/OTA_Namespace_and_Versioning_2003A.pdf