If you are using any 2g, 3g or 4g phone do not support the volte so this app is best option I am using this app by connectiong to my jiofi it have lots of feature like you can send any file like whatsapp from jio4gvoice which is called RCS( rich communication service) which supports even pdf file to send over any network like it is send over the 4g network by this.this app is best for communication for HD voice call.this app contain conference, smart calling, file sharing and selfie sticker best app exeperience