Moodle has been upgraded through three major generations and is now running the latest release available as of this date.
Much has changed.
One of the major changes is that not all of the add-on modules we used in Moodle 1.9.x are available in Moodle 2.2.3. We will be installing those that are in the next few days, so if you don't see a feature or resource you are accustomed to using, please check back in a day or two. Also, you can always let us know what you're missing and we'll try to replace it.
We encourage all the users of the site to experiment and become familiar with the new Moodle. You may want to refer to the official Moodle documentation for pointers and you are always welcom to contact us should you get stuck.
Good luck and we hope you enjoy this new release.
The Moodle Support Team