ODF 1.2 - version info in meta inf?

While working on adding a Digital Signatures specification to ODF 1.2, I
stumbled over the fact that I need to know if a document is v1.2 or
older, because the specification is a little bit different to the
implementation we have right now in OpenOffice.org.

Of course I can add the version info to the signatures stream, but I
wonder if this isn't something that should be available "globally" via
META-INF?

Malte.