We all know it's not 7, cause nobody got an upgraded cache even after clearing it on week 1.
I got a cache upgrade after reset when I had 10 heroic kills, so at most it's 10 kills.
Has anyone had a cache upgrade after only 8 or 9 kills? Currently at 8 mythic kills, maybe 9 if we kill nythendra and having that extra mythic bag next week would be really sweet, as I have almost no use for heroic items outside a life relic or a swarm trinket for my off-spec.