Reliance Jio is a disruptive 4G network in the India. With 4G penetrations taking up rapidly in India, all the new devices comes with 4G and voLTE support. But the old devices are restricted to this expansion because of lack voLTE support. Hence Reliance Jio solved this issue with Jio4GVoice app.
The Jio4GVoice app allows you to call and text to the mobile numbers. You need to a have an active Jio 4G connection and the app installed on the device to all other mobiles.