source: http://eu.battle.net/sc2/en/forum/topic/1710175851I don't know if this is common knowledge or not but I haven't found it anywhere so I thougt I'd share:
Zerg:
*Corruptors: Now deals +4 damage to armored, but they no longer do additional damage to massive (aka. +4 dmg vs armored, -2 dmg vs massive).
*Fungal Growth: Now lasts 4 seconds down from 8. It still does the same damage tho so this basicly means it'll do double the DPS as it used to, but last half as long. In other words, you'll benefit alot more from having several infestors where energy won't be the limitation. Fungal growth will also do additional damage to armored. I don't quite remember how much but I think i recall +20%.
Terran:
*Stim: The research timing has increased. I don't remember how much tho.
Protoss:
nothing
I have no idea if this is what it's going to be, but the source seems reliable.
Tbh increased stim time can be a pretty sizeable nerf and to me it seems if there is one race too strong it's protoss, but they dont seem to get any nerfs.