We recently made a very similar switch and created a new Joomla 3.3 (replacing our old Joomla 2.5 site) & updated DTReg to 3.09. I experienced/am experiencing a few glitches - so I wanted to pass this along to anyone whom it may help:
While using cPanel and then phpMyAdmin to export the DTReg tables from our old Joomla site to the new Joomla 3.3/DTReg 3.09 site, I had difficulties exporting my DTReg tables - Only some of the data would copy. I FINALLY figured-out the problem was a simple matter of increasing the 'Maximal length of created query' to a ridiculously high number (I used 500000000) and then all of our table info was exported, no problems. This may be obvious to those who work regularly with SQL tables, but I was a novice. I hope this helps you.
Now that we have officially launched the Joomla 3.3/DTReg 3.09 site, we are experiencing another quirk: For events created as part of a repeating series, groups are only being charged for one member.
I have a Field that determines the total group price that is set as 'required' and also a 'change fee' field in the overall DTReg 'Fields' area. However, when I go to create an event that is part of a repeating series (as almost all of our events are), upon initial creation of these events the field that is configured as 'required' is showing as 'no' (as in, NOT required) in the 'Required' column and the ability to change from 'no' to 'yes' is grayed-out. In the column 'use for this event?', if I change the radio button from 'Default' to 'group' or 'both', THEN I can change the 'no' in the 'Required' column to 'yes'. BUT - the change will only take effect for the first event in that series. In order to make the change to the remaining events in a series, I have to open each subsequent event and make the same change. This is VERY INEFFICIENT, as we can have up to 15 events offered per day, with each event being part of a repeating series that may contain up to 25 events.
Too much work!
If you experience this same issue, I would love to know how to correct it.
Good Luck!