Upgrading a very old version to the latest one, possible?

Hello, I am trying to upgrade version 2.0.4 to 3.2.1. Is this a matter of replacing the old files with the new files? Was there a structural and fundamental changes in between the two (e.g., changes in the MYSQL database structure and file name)? If so, do I need to do the incremental back-up? Could you advise?

Thanks.