unify 1.8 combat to 1.9+ with a new update

The Minecraft 1.9 update changed the fundamental mechanics of combat in vanilla Minecraft, and thus frustrated the community of skilled PVP players playing on that version. For that reason, 1.8 players refuse to play later versions and stick to their current playstyle. 

Contrary to this is Minecraft's core philosophy of inclusivity; the game of Minecraft is designed to attract a large amount of different play styles, such as technical, combative, creative, and minigame communities. Minecraft seeks to bring these all together, and recent updates reflect this idea of giving more players more ways to express and fulfill their preferred playstyle, such as the Chaos Cubed update providing opportunities for minigames, technical contraptions, and unique combat mechanics.

in order to  "lure" the 1.8 players back into the current version, a similar approach is needed. A "two birds with one stone" solution that would give new opportunities to existing players and give back the 1.8 players the combat they desire.

My suggestion is to implement one of the following

-a gamerule that toggles between 1.8 and 1.9+ combat

-a group of items that functions identically to 1.8 combat (such as a "shortsword" item that functions like the 1.8 sword or a fishing rod that stuns instead of reeling)

-a beacon effect titled "honor" or something similar that changes the combat mechanics to their 1.8 versions

Through this, we can find a middle ground to appease the 1.8 and 1.9+ combat players.