Thats work around, if can't afford to have down time/transaction loss, and the database is up and runing. If you can, restore it from cold back up and apply redo log... still you should be okay if your transaction rate is not that much and redolgs are of sufficient size.

Not sure whats your situation. Solution is based on your situation.

I don't see any work around as binaries got upgraded. If you are looking for specific oracle product option which is not working say like replication or whatever... see the scripts comments for those options in $O_H/rdbms/admin directory...
and try to rerun prv version script for that option. Just trial.