You can replace the function with those to use mod-gui

function InitPlayer(player)
    mod_gui.get_button_flow(player).add{name="btcharxp", type="sprite-button", sprite = "entity/player", tooltip = {"panel-title"}, style = "mod_gui_button"}
    SetupPlayer(player,true)
end

function resetAllPlayerStats()
    for _, player in pairs(game.players) do
        if not mod_gui.get_button_flow(player).btcharxp then
            InitPlayer(player)
            else
            SetupPlayer(player,false)
            end
        end
end

Thank you Y.Petremann, I´ll use it.