You are a life saver. I am able to enable wifi calling for Jio network in India. I have been struggling with very poor reception in my home and with this the call is super clear. The right code has an asterix at the end of the code which you posted.
Here is corrected Typos from earlier posts Correct Code is *#*#3642623344#*#* 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. Edit: 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.