if you mean an upgrade in performance, no way to know without knowing the details of your existing controller. Controllers can have the exact same specs on the label, but perform completely different. The seat of the pants performance difference is more related to phase amps not battery amps, and some controllers can output more phase amps with the same battery amps, so need more info.
As far as the ratings of the controller in the pic, it’s basically saying the controller can run higher current at lower voltages and lower current at higher voltages before destroying itself. 36x50 =1,800w. 84x40=3,360w. The higher current limit may be based on component ratings, and the lower current, higher voltage, may be heat related (over 3kW continuous and the controller gets too hot).
If you are going to replace your old controller anyway, you could always try a shunt mod on the old one first to see if that gets you enough performance gain to satisfy you for the time being.