I am using JIO Sim from last one year. I have good network coverage for Jio at my home.I am staying at Kochi.I took this connection for free calling and high internet 4g speed.At the time I took this sim, jio offered good speed and uninterrupted 4g calling.But the 4g calling quality degraded gradually.It takes long for the jio 4g voice to get online.When it gets online and we dial a number, in between itself the connection is lost.Once the call gets connected after multiple attempts during the call itself the network is lost.I feel really irritated and exhausted everytime I make calls.This app is really of no use.Even after having a 4G enabled handset honor 5x I amnot able to make 4G voice calls.This app performance is really poor.The purpose of 4G voice calling is not all met.I took another sim of different operator to make calls as the issue become prominent .Jio4gVoice really requires performance upgrade otherwise noone will use it.