Sense Dead: 0->1
Animate Dead : 1->2
Dormant Spores: 1->2
Concentration: 1 ->2
Mass Animation: 0->1
Knowledgable Undead: 0->2
Armored Undead: 0->1
Do my existing zombies gain the knowledge? Next time a program? Or not at all?
you would have to let their duration elapse back to corpses and re-animate them to get the new bonuses