In 4.2 transaction table entries will have a 'state' field added. To be save upgrade/downgrade work in 4.2, we should be prepared to encounter transaction table entries with a 'state' field in 4.0. If the 'state' is 'committed', we should treat it the same as if there was no state field. If the 'state' field is anything other than 'committed', then we should treat it as though that transaction table entry doesn't exist.