Step #1: Go to H1Z1: KOTK on steam
Step #2: Right click it and go to properties
Step #3: Click Local Files and Browse Local Files
Step #4: Scroll down and open up Useroptions file
Step #5: Copy and paste reticleClassicMode=1 under the "UI" sub heading.
Step #6: Save the file and open game
Not sure if anyone has posted about this already. Good luck in your games. For some demo on how to do this, just go check out the video below by Napo II.