I would assume the top and bottom voltage ranges are the responsibility of the controller and charger.
All the new battery provides is increased capacity through the use of larger-capacity lithium cells. The battery is comprised of 52 individual cells, each slightly larger than a AA cell. 13 cells are in series, giving a nominal 48 volts. There are 4 such banks, so the Ah rating is just 4x an individual cell rating of, typically, 2.5 Amps for 1 hour (2,500mAh). So the total is about 10Ah. The new pack is just made of cells with a rating of 3.5Ah, or 14Ah when in parallel. 14 x 48v = 672 WattHours. Nothing else changes. It'll take longer to charge but will give increased range.