This update brings Archetypes into the fold. Archetypes are a new option for playing classes. When you create a character, there will now be a little window that contains the base class and associated Archetypes you can choose from. The first three arrive with this update and are available to all, with more to be released (possibly to VIP or a rotation). Added today are Dark Apostate (base class: Cleric), Sacred Fist (Paladin), and Stormsinger (Bard).
The Temple of Elemental Evil also gets an update in this patch. The first part has now been divided into multiple quests, the new Legendary difficulty is live, some encounters got tuning, and the rewards have been adjusted.
If an ability requires you to be a specific class, and the archetype that is associated with that class will qualify. Archetypes let you play existing classes, and they have different requirements. They can have different enhancement trees, class Feats, class spell books, and Alignment restrictions that differ from their Base Class. There's also a way to multi-class into an Archetype, with some restrictions. They must have different base classes, for one.
The new Archetypes system also has a way to fit into the Heroic Past Life system. If your class is in an Archetype, you'll also earn and unlock that Archetype's past life. You can also use the Past Life with Archetypes to complete some requirements if you haven’t earned Heroic Completionist yet.
Overall, this new system gives you some new ways to branch out and to complement your playstyle or add some additional options and skills you might have otherwise missed out on.