Add compatibility with spigot but paper and spigot have two method of storage for item.

if you change your server to spigot/bukkit use the command : "ah admin transfertToBukkit" or "hdv admin transfertToBukkit"

if you change your server to paper use the command : "ah admin transfertToPaper" or "hdv admin transfertToPaper"

delete lang file to regenerate it