While version 1.8 introduced the big features (Ocean Monuments, Rabbits, Armor Stands), 1.8.1 refined them:
Originally released in late 2014, with minor security patches like 1.8.8 following in 2015.
This version addressed several exploits that allowed players to crash servers. Major Features & Changes
Significant improvements to the chunk rendering engine and game physics to reduce "lag spikes".
Обзор Minecraft 1.8.1 (Обзор Майнкрафт 1.8.1) Герон YouTube• Nov 25, 2014