When 450 was on design board, engineers thought that Side Pedal/Step was not necessary. This is because sitting on one side of the vehicle is a safety hazard as gravitation centre shifts.
Given the utility and demand for it, Ather was considering if an accessory can be made. However, given the current design, it is very challenging to add a side-step, as there is no location where it can be mounted without making it a big contraption.
As for future if there are hardware added features, it will not be possible to add them to current versions, as they most likely will need a design change in some component, as opposed to being an add-on accessory.