The Shadow War Armageddon Rulebook is now up for pre-orders and along side it are the two new faction you can play, Adeptus Sororitas and the Inquisition, now available for free download on the Warhammer Community site.
https://www.warhammer-community.com/2017/04/22/shadow-war-armageddon-pre-order-and-downloads/
Inquisition
https://17890-presscdn-0-51-pagely.netdna-ssl.com/wp-content/uploads/2017/04/ENG_158_163_INQ.pdf
Adepta Sororitas:
https://17890-presscdn-0-51-pagely.netdna-ssl.com/wp-content/uploads/2017/04/ENG_116_121_SOB.pdf
Counters
https://17890-presscdn-0-51-pagely.netdna-ssl.com/wp-content/uploads/2017/04/Armageddon_Counters.pdf
Rosters
https://17890-presscdn-0-51-pagely.netdna-ssl.com/wp-content/uploads/2017/04/ENG_Roster.pdf
You can also pre-order just the rulebook here
https://www.warhammer-community.com/2017/04/22/shadow-war-armageddon-the-rules/
Shadow War: Armageddon $40