[Resolved]  Vivo Mobile India — software update problem

Hii, i bought vivo y51l mobile 2 years back, but i didn't get any volte update. But my friend got update. What's the problem. If the update is available please notify me or tell me what to do to get update. If there is no update availabe please consider this and try to get update. This is the major problem of vivoy51l mobile users. Please send me the solution to this.