Updating Production Lib

I have found that certain functionality works perfectly in development and then not in production. At this point I have found Linking and passing parameters and a bunch of Ajax functions are not working in Production.

I have to assume that I need to update my Production Lib. My worry is I dont want to have to reconfigure production databases all over again (we have many).

Please can someone tell me what folders in Production/Lib I should update?

Thanks

Larry