This morning's patch was to correct a problem with the EverQuest client that caused those trying to exit The Hole or The Plane of Hate to crash and not be able to reenter the game.
As part of this patch we've added a new /-command. /dynamiclights [on/off](on by default) will turn on or off your ability to view dynamic lighting in game, such as that created by a torch or lightstone. Dynamic lighting uses CPU power. We've found that those participating in large raids with many people can increase their framerate by setting this to off for the scope of the raid.
New settings to this option will take place after you zone, and the preferred setting is stored in the EQCLIENT.INI