Here is corrected Typos from earlier posts
Correct Code is
Rule of such code: It starts with * and whatever your pre-text before numbers should mirror post-number code. After entering code, screen should go back to dialer mode, as if nothing happened. You don't have to press dial button.
WiFi calling has been enabled for my both Sims, Jio and Airtel.
I still need to test WiFi calling from home. Although, 6z receive better signal, JIO and Airtel both give $hIt coverage at my place on rotational basis. ? . I hope this works for me.
It seems that trick is working and I got the VoWiFi icon for Jio. This trick only work till phone restarts. Once phone is restarted, you will loose the VoWifi.
However after the update it's gone.
As phone restarted. You have to enter the code again.