From:cityofheroes.com

The next free expansion coming to City of Heroes and City of Villains, Issue 12: Midnight Hour, has entered Open Beta Testing. This means any and all subscribers to the game can log into the Training Room and try out the many additions and improvements included in Issue 12 for themselves! If you haven't been to the Training Room before, click here for instructions on how to configure your computer to do so.

To read the many changes in the current version, join us on the Official Message Forums to view the patch notes.