ViaHitbox

This fix has been implemented into ViaVersion 2.0.0, so just enable 'change-1_9-hitbox' and/or 'change-1_14-hitbox' in your ViaVersion config.

This very simple and small addon for ViaVersion fixes velocity bugs due to version specific hitboxes.

As a result of player hitbox changes in the Minecraft versions 1.9 and 1.14, you will run into this problem when using ViaVersion on a server lower than 1.14.

PvP servers are probably affected the worst: Players will get stuck when being hit whilst standing under a block, resulting in them not receiving any knockback and bugging back again.
If that's not a problem for you - great, you won't need this plugin! Else, you know where to find the download button

This plugin offers you the options to

• A - fix hitboxes for 1.9-1.13 players on 1.8 servers
• B - fix hitboxes for 1.14+ players on a server lower than 1.14

Though there is a catch to the second option (which is why it is configurable separately) - 1.14+ players will be able to go under entrances with a hight of 1.5 blocks (as that is the new hight of their hitbox).