Since now PVP can be toggled in-game with /gamerule pvp and no longer requires to restart the server, /pvp [true|false] command possibility has been removed. /pvp command now only starts the vote. However, unlike vanilla, in Paper gamerules values are different for each world, meaning that executing /gamerule pvp [value] in a dimension changes that value only in that dimension, so the plugin ensures that when /gamerule pvp is executed, the new PVP state is applied to all worlds.