Reference : https://hibernate.atlassian.net/browse/HHH-8893 https://hibernate.atlassian.net/browse/HHH-8894 I wanted to start a discussion around some planned changes relating to processing XML mapping files. The 2 issues above cover the bulk of the intent: 1) move to a single format for expressing object/relational mapping in XML, based on the JPA ORM XSD 2) combine that with transformations for numerous known formats to a definitive format for processing. The basic idea here is to have just one XML format that we actually process as input (StAX+JAXB). It would be a derivative of the latest JPA ORM XSD ("extended" for Hibernate-specifics). We would still accept numerous other forms (hbm.dtd, "straight" orm.xsd versions 1.0, 2.0, 2.1) and transform them to the "extended" schema. This transformation would be available on-the-fly as well as via a build-time task. This opens up the question of exactly how we want to mix the Hibernate-specifics in with the JPA entity-mappings schema types. For example we might want to take this opportunity to "clean up" the things we expose via XML, or unify them. For now, I'd like to just make this an open call for suggestions of things people would like to see changed in XML mappings.