by Tim Hunt.
Normally, rather than relying on a specific version number, instead you just analyse the form of the data. E.g. if you add a new property, say 'colour', then in the restore, if the colour property is missing, then you set it to a default.
However, I think the version number is there. Moodle backups are just Zip files. If you unzip, and look at the XML, I think the version number is in there (but I am too lazy to check myself now).