migrate from TS6.1 to TS6.5

System

Has anyone successfully migrated a PRODUCTION server from TS6.1 to TS6.5? I'd like to get some insight:

1. Do you choose to upgrade from TS 6.1 to TS 6.5 or uninstall TS 6.1 and install TS6.5?
2. If you have some long running workflow jobs in the production backing store, after the server converted from TS 6.1 to TS6.5, are those jobs created under TS 6.1 working fine?

I have been testing on a fresh installation of TS6.5. And I will need to convert a production TS 6.1 server to TS6.5 soon.

Thanks.