The Fortress of Solitude is an eight-man raid which will reward successful players with Marks of Distinction, which players can use to purchase powerful new gear. The update also includes new high-level armor sets, including sets for heroes featuring Superman's logo, and sets for villains emblazoned with a 'Z' for "Zod." New hard-modes are also making an appearance, in the form of the Batcave and Hive hard-mode alerts. All this new content is available now, so jump right in and fight for some peace and solitude!
UPDATE: Sony Online Entertainment released two corrected details today, August 4th. Players will earn Marks of Krypton good towards purchasing new gear in the Watchtower or Hall of Doom, rather than Marks of Distinction. There is no Hard Mode Option for the Hive Alert.