upgrade from version 3?

I would love to upgrade from version 3 to version 4, but am truly afraid of losing my events:

http://www.unquapta.org/cal/calendar.php

I made backup copies of the tables (ltw_usersbak for example) and left existing tables.

Is that all I need to do to ensure my events don't disappear?

Will my events appear like magic or will I have to know how to use the backup tables to bring them about?

Any success or sad stories out there?

My main reason to upgrade is to use that very cool tool tip addition in featured in a nearby message.

The upgrade from rev 3 to 4 should work fine.
The installation script adds all the new columns without deleting any old one.