Pathfinder RPG 2nd Ed: Fires of the Haunted City - Rules of Play says:
Age of Ashes is the first Adventure Path using the brand new rules for the Pathfinder RPG. This fourth adventure is for 12th-level characters, and also includes a gazetteer of the dwarven city of Kovlar, a discussion of the evil dwarven god of toil—Droskar, and a wealth of new rules options for player characters to discover, along with more than half a dozen new monsters!