Use Reliance Jio 4G In 3G Phone

NOTE: TRY AT YOUR OWN RISK, I AM NOT RESPONSIBLE FOR ANY RISK.
1. Open Engineering mode in your phone, if you don’t have download from here:http://goo.gl/Engineeringmode & Install.

 2. Open app and Select MTK settings > select preferred network option.

3. You will see list of network. you have to select 4G LTE/WCDMA/GSM and Then Restart your Device.