First of all you can make sure that the game is updated by checking the version (it has to be 1.2.0 or greater).
The new patch didn't add any new skill, so the manor is untouched. Every new piece of content has to be unlocked, if you're interested in how you can read the spoiler below (informations taken from the Special items page in the wiki).
When you pray at a Spiritual Shrine, you now have a chance to get one of the bosses' Obols, among other items. After you die you're forced to give this Obol to Charon. Doing this unlocks the powered up version of the corresponding boss, that you will find in the appropriate room in the castle, but only after defeating the normal boss. This fight is different from the usual, since you're forced to fight the "buffed up" bosses with a specific combination of classes, traits and spells, each one specific to the boss you're fighting. This combination replaces the one you've chosen for this challenge only and if you fail the fight, you'll just be teleported outside the room, with the class you've chosen at the beginning of the run, letting you enter the door again and retry (as many times as you want).
After you've fought all of them, you will be able to get the Traitor's Obol from a Spiritual Shrine. Then, if you enter any boss chamber that you've previously completed, you will fight as Johannes against two copies of yourself. After you've beaten this last challenge, you'll have access to the Traitor class. Using this class to enter Johannes' room will then give you the last achievement, "Katagelasticism"