Firaxis' big new autumn update (or Fall Update, if you must) for Civilization 6 is live and available to download now.
Its main focus is on overhauling the way that religion works, and it aims to make the religious path a more enjoyable, tenable approach to winning the game. To that end, the update adds new religious units, two new Pantheons, and new Founder, Follower, Enhancer, and Worship Beliefs. The latter unlock the ability to build a new medieval land combat unit, the Warrior Monk, and there's also a new Guru religious support unit, which can heal other units.
As part of a broader series of religion-based improvements, all religious units now move on their own layer (similar to Trade Units and Spies), and a new 'Condemn Heretic' unit action has been introduced, enabling military units to eliminate religious units in their tile. Additionally, religious units now exert Zone of Control and receive Flank and Support bonuses in religious combat.
Wrapping things up for the religion overhaul, religious pressure has been added to both ends of trade routes, there are eight new Relics, and Missionaries have had their long-term usefulness increased. All this is accompanied by a number of improvements to the Religion Lens interface, designed to increase overall usability and readability - which should hopefully make managing religion a lot less of a headache.
Beyond this, the autumn update adds a massive list of more general UI enhancements, AI improvements, balance changes, and bug fixes, all of which can be found in exhaustive detail in Firaxis' official patch notes.
Finally, Firaxis' two new, recently unveiled civilisations, Khmer and Indonesia, are also now available. These are free as part of Civilization 6's Digital Deluxe Edition, but if you don't have that, they can be purchased as a two-faction bundle for Ł8.99.