I'll give a rundown of some of the highlights:
- Vastly improved UI. Utilizing JQuery and JQuery UI for theming. A more sensible and powerful event form.
- Multiple calendar support
- Improved user support, including admins for specific calendars, and user groups.
- Support for timezones
- User selectable language/timezone
- Improved translation support. Included script to build translation objects and no longer reliant on built-in gettext support.
If you've been using PHP-Calendar 1.1, now is the the time to upgrade. There's an included script to move over your old events. It could use a bit more testing and feedback, but it's ready to use.