It would be useful to have a public interface for determining the database format when running in soft upgrade mode. In the derby-user thread:
Evan pointed out he was using an undocumented property 'DataDictionaryVersion' for this purpose, but this is not ideal because it does not conform to the normal derby.* naming convention and is not documented.
DERBY-4255 determined that there are not currently DatabaseMetaData methods that achieve the same result.