For now, there are no plans for upgrading to 4G for the 450. It’s something Ather is exploring, but can’t guarantee that it will be possible for the current generation of vehicles.
In the 3rd owners’ meet, Ather team has clarified that Vodafone does not has any plan to shut down its current 3G service any time soon.
Also, the 450 is capable to fallback to 2G if the 3G service isn’t available at a location. The data bandwidth will reduce, but the functionality will not have an impact.