From Warhammer Community:
The General’s Handbook 2017 will again be an invaluable resource for any Warhammer Age of Sigmar gamer.
For open play, the multiplayer rules have been massively expanded, and now include Triumph & Treachery – devious rules for mid-game betrayals.
Narrative players are about to get really spoilt. With Path to Glory soon to become its own stand-alone expansion, this section has been freed up for a huge amount of new content in the 2017 edition. Highlights include rules for siege warfare in the Mortal Realms and Time of War battlefield rules for locations in every realm (even the one’s we haven’t been to yet!).
Matched play is set to get plenty of updates too. These include new Battleplans, new rules of one, and updated points for units in every faction in the Mortal Realms.