#1 - Nov. 8, 2016, 11:13 p.m.
Beginning this week, with the opening of Trial of Valor, the end-of-run chests for completing a Keystone dungeon at level 11 or higher will now give loot with a base item level of 870, up from the previous base of 865 for completing a level 10.
Additionally, if you are able to clear a Keystone dungeon at difficulty 12 or higher, your Order Hall cache for next week will contain loot with a base item level of 885. Note that this change does not apply to the cache you can open this week, which still has its base item level capped at 880 if you were able to complete a level 10 Keystone dungeon last week.
Of course, keep in mind that these rewards still have a chance to roll Warforged or Titanforged; the item levels listed above are merely the guaranteed minimum you will receive.