MVNO VoIP is Voice over IP, which essentially what all 4G / LTE forward voice is, as there is no legacy switched voice over non legacy networks. While MVNO VoLTE and MVNO VoLTE Roaming is taking a while to permeate and will take longer still with 5G Voice, Virtuser has implemented VoIP applications for it’s MVNO, Travel SIM and IoT customers to enable a transition that has a much smaller resource footprint and is much more versatile than Voice over WiFi and VoLTE proper, as it can run over any decent data connection securely, anywhere