what to do for VOLTE in India's jio network? Actually my friend bought me a mobile from UK , its SAMSUNG J3(2016). But now i now need to use VOLTE in India in Jio 4g network, which is not available in the foreign made by default. Which firmware i need to use? Also please tell me how to do this?
If you want to flash a new ROM then you should collect essential information from XDA forums about your device. Flashing a new ROM is a risky task so you must create a backup or something to fix your handset.

If you don't want to risk anything then use Jio4GVoice https://play.google.com/store/apps/details?id=com.jio.join&amp;hl=en . You can Call, SMS, etc without a VoLTE enabled handset.