Minecraft 1.16.3 is a minor update to Minecraft Java Edition, released on September 10, 2020, which fixes two major bugs.
The content of Minecraft 1.16.3 is identical to its release candidate, the only difference between the two is a change in the data and protocol versions. Which means Minecraft 1.16.2 and Minecraft 1.16.3 clients and servers are not cross version compatible without plugins like ViaVersion.
Update to 1.16.3 addressed the bug where Piglins, Piglin brutes, Hoglins and Zoglins have trouble pathfinding to the player when attacking. Also duplication glitch where giving an item and a gold ingot to a baby Piglin and killing it duplicates the item was finally fixed.