An advanced feature is the use of the attribute strategy on a top level metadata field: Metadata Strategy.
When the metadata format changes during a release, a new namespace with that release number will be present. However you can still keep submitting using the namespace of the previous metadata versions. Note that not every release of MediaHaven (4 per year), will have a new metadata version, in which case the metadata version number keeps the version number of a previous release.
MediaHaven has the following list of metadata versions
You can keep using the old format External Metadata [deprecated] with the system converting the old format into the new format under the hood. But we encourage the customers to switch to new formats because it will be default for the documentation and new features.