We've just updated this site to Moodle 2.4.1.
Plugins of course don't work with every version (many are very specific to an exact version).
We will be making some changes and updates during the next two weeks as we will use this site at the Moodle Moot conference in Vancouver. We generally update the site every 3 months or so.
However, we can't alter Roles on this site for people (sorry), it's free but has to be very low maintenance to keep it that way
The best place to read about the Booking module (current state) will be on the Plugins page on Moodle.org (or from the links on the Bookings page).
Hope this helps, Stuart.