Prior to this, assuming you have enabled calling via wifi in the simcard setting.
Turn on airplane mode, after that connect wifi, and use the phone to call using simcard..
If you get connected the phone call, the vowifi is working..
If you get and error turn of airplane mode to make a call----> now dial *#*#4636#*#* and a pop up display triggered, now go to the phone information 1 and phone information 2, scroll down and enable "Mobile Radio Power"..
https://www.youtube.com/shorts/K1fWZxi_kBMNow use the simcard to call again (still in airplaine mode with wifi connected), if the call get connected, vowifi is working..
For redmi phone to disable vowifi check: *#*#869434#*#* , repeat to enable
For redmi phone to disable volte check: *#*#86583#*#*, repeat to enable
Basically tested redmi 8 for the vowifi for Digi, celcom, umobile, hotlink, all working for vowifi, with the above method, so the device dependance is not really main factor. But only umobile will get the icon vowifi automatically, the rest telco digi celcom hotlink no vowifi icon appear but the above method managed to get vowifi working for digi, umobile, hotlink, celcom...
Thanks..works on my poço f3 however the call kinds of slow. Takes a fews seconds for the calling dials tone