When did this change to Necromancer Sacrifice happen?

My recollection is that sacrifice PERMANENTLY removed your ability to summon ANY of that type of minion.

Today I see that it now means you can TEMPORARILY (i.e. toggleably) remove your ability to summon HALF of the number of that type of minion.

I'm just curious if these are recent changes or if they've been around for a while. I only played necro for a month or two after release, haven't touched it since.