The newest version of Naga Viper has an attenuator knob. This control acts like a level control for everything in front of the Naga Viper, letting you shave some heat from the incoming signal before it runs through the proverbial gears of the booster. This leads to less saturation and undesirable effects and more treble-boosting goodness going into your amp.
The transistor in the Naga Viper has also been replaced and the circuit tastefully reworked to accommodate players of all stripes. Some players will leave the Attenuate control all the way up, and this design choice is for them. By swapping out the transistor, the Naga Viper is even hotter than before, with extended ranges for both Heat and Boost controls. Diming both controls now gives a slight edge compared to V1, opening up the range of the attenuator as well.