Volte

"In India, 4G VoLTE exclusive network such as Jio doesn’t allow to make calls from the iPhone 5S, unless the user installs the Jio 4G Voice and SMS app".

This telecom company kills iPhone 5S and other non-VoLTE devices - Deccan Chronicle

Also see: Make phone calls with Voice over LTE (VoLTE) - Apple Support

"You can make high-quality phone calls with VoLTE on an iPhone 6 or later. To make these calls, both phones need to work with VoLTE".

shahid40 wrote:

my iPhone 5s not calling directly with ipad with jio sim because of volte but it is volte support i requests to you please enable volte in next update

That's not going to happen.

#1: VoLTE requires an iPhone 6 or higher.

#2: The iPhone 5s will not be getting any more major updates at all.