The June 5th, 2020 Android9 update at least has new wifi calling icon 
FP3 A.0134, Android9 OS update, security patch level June 5, 2020
maybe it has better wifi calling capabilities as well. check for yourself and report back.
The June 5th, 2020 Android9 update at least has new wifi calling icon
maybe it has better wifi calling capabilities as well. check for yourself and report back.