Hello,
I've tried to request this through live support but it never went through.
Carrier name: Digi HU
APN settings:
Address: "internet"
MCC: 216
MNC: 03
Auth type: PAP
APN type: "default" (or "default","supl")
Even though dialing "*#*#3642623344#*#*" mentioned here on the forums enables the "Enhanced 4G LTE Mode", "Wi-Fi calling", and "Carrier video calling" settings, they do not seem to work. Even in the Phone info app (dialing "*#*#4636#*#*") shows VoLTE and VoWiFi as unavailable in the IMS Registration menu.