METS serialization with Digital Object versioning

I'm looking for a solution to get a version identifier in a METS representation of a Digital Object. I could not find anything related to versioning in the METS schema.

Naively i thought something like this would be possible:

<mets:mets xmlns:mets="http://www.loc.gov/METS/" 
     OBJID="some-id-xxx" 
     VERSIONID="version-xxx" 
     LABEL="some-label">
      ...
</mets:mets>

But there is no such thing as VERSIONID in the METS specs

Is there a general way to do this? Does a new Version always require to be created with a distinct OBJID and a reference to the former Version in the Source metadata?

fas

• metadata

Comments

• anarchivist: Are you trying to indicate a version of the METS representation or of the object itself?
• fas: the identifier should be for the object itself.
• Jakob: Has your question been answered (so you should mark an answer as accepted) or do you have additional questions or comments? What's your solution?
• fas: still working on a solution.

Answer by Jakob

One could embed the version in the descriptive metadata or in the administrative metadata in another metadata format, such as Dublin Core or MODS. I'd treat a version identifier equal to an edition identifier. For instance in MODS there is an edition child element of originInfo.

Comments

• fas: the problem i have is that we are exclusively using DC for the descriptive/source metadata set in our backend, and i can't find anything usable as a Version Identifier in there: http://dublincore.org/documents/usageguide/elements.shtml
• Jakob: Yes, there is no specific *edition* or *version* field in DC. The property would surely be related to dc:identifier, so you should use this property, similar to bibo:edition in the Bibliographic Ontology. For example `dc:identifier = "version 1.3"`.

Answer by Ed Summers

The METS documentation talks about using mets:fileGrp to record versions of a particular object: for example an object that is available as a TEI transcript, an MP3 and a WAV. These could be linked together in time by their created attribute. But I get the sense that you are talking about versioning in a different way, similar to how it is talked about in revision control systems? The answer to Mark's question is important. Do you want to version the metadata about the object, or the objects themselves? If the latter I think you can probably bend mets:fileGrp to your will. If the former, perhaps you need a new METS document that is linked somehow to the previous one, via the identifier? If there isn't anything in METS it might be a good use case for RFC 5829.

Comments

• Jakob: Looks like we have at least three possible notions of versions: revised object versions, different representations of the same object, and different descriptions of exactely the same object.
• fas: Yes i was talking about an Identifier which encompasses the whole digital object. The idea is to create a new version every time some property of the object has changed. So if someone were to update technical metadata of a file contained in the object a new version of the object is created referencing the changed metadata while the original object stays the same.