Good news unlocked customers with the new update Galaxy S10 U1 version now has VoLTE on AT&T!!
@uservgPkzcO59v it's turn On by default. If you make a call and the icon stays LTE on the top you have VoLTE on.
@userV5ZsZ1e2CX No idea they havent receive a go signal from AT&T yet i am hoping next month if there is any update but it should be one of the updates anytime.