Hi, I'm a different Joe but maybe I can help.
mojoPortal upgrades are quite simple. All you should need to do is follow the instructions on the Upgrading from Previous Versions page.
You shouldn't need to manually modify the DB at all for an upgrade from 2.3.0.1 to 2.3.1.3. Be sure you make a backup of your current site files and database before doing anything.
HTH,
Joe D.