I got DayZ SA theres a long time, I started to play it again since 1.0 and it seems that theres no a difference between hitting someone in the head or any other part of the body. This is completely dumb and I hope that this happened by accident in one of the patches (I know that things like this can happen as I am a hobbyist game dev). There no reward for a well placed headshot.
In DayZ reddit, theres alot of clips of people shooting others in the head with snipers and they are simply running away, which is extremely unrealistic and unfair.
(Proof included in the Steps to Reproduce).
The issue with the headshots is infuriating and I never felt more disappointed with a change in the game and trust me when I say i've been disappointed loads of times as so many things were cut off the game but I never wrote a feedback report since I believe these things will come back at one point even though theres no promise of that.

But theres another big issue with combat that needs to be looked at too:
The damage as a whole feels "dumbed" down or nerfed in this current version of DayZ, you can only safely kill someone if you have 5.56 caliber or higher, it takes 4-6 shots of these calibers now to kill someone instead of 7+ of lower calibers if they have a vest and helmet, in older versions, Im pretty sure that 2-3 shots of an AKM would kill you, with no vests one bullet would be enough to incapacitate you. Low caliber guns such as SMGs or pistols are useless against targets with vests and military helmets. (Proof Included in the Steps to reproduce).