Rafa0612 , via OnePlus 7 Pro , Jun 2, 2020 : I have OnePlus 7 Pro running the latest oxygen OS (10.3.3.GM21AA). The VoWifi option is showing under the sim settings and I've set it to be the preferred option when calling. In both the sim (Airtel and Jio) I've enabled VoWifi, but it doesn't stay connected to it for long even though when I have a stable high speed internet connection. I've tried connecting to different ISPs via wifi but had the same issue with all of them. It connects for some time and then switches back to VoLTE. Someone's recommendation on the OnePlus forum to disable wifi scan throttling from developer setting, did improve this a bit but still the problem persists (and due to this change in setting, there is a significant battery drain). Any tips or suggestions to make VoWifi stay connected instead of it switching back to VoLTE ? It seems like a very big bug and I've seen a lot of my friends and members of the forum facing the same issue.