[otrs] Difficulty in upgrading existing install from 2.0.4 to 2.2.6??

Hello, I have a running 2.0.4 OTRS installation and I am considering updating it to 2.2.6. Can anyone give me an idea of how difficult or problematic this might be? Is it as simple as replacing the binaries or has the mySQL tables and indexes changed significantly as well? If there are significant changes has anyone developed a tool or perl script that assists in the conversions? Thanks, --Jeff