Jio4gvoice is needed for calling and messaging to jio sim if your phone is not in 4g jio service.
But it has number of problem, I face problem many times when I call, but it connect after 4-5 time, it is not good as other application of jio.
And I also face problem to sending message, it has no any facilities to saving new contact but it is necessary for calling so I use it.