Google Fi is an MVNO service offered by Google. It allows you to make phone calls and send SMS messages through the use of the Internet. Google Fi uses the T-Mobile infrastructure, which means that Google itself is forced to make changes to its service to the extent that T-Mobile does. From January, Google Fi will no longer support phones that do not have VoLTE, the standard way to make phone calls via the Internet.
From January 2021, Google Fi will not support phones that do not have VoLTE functionality. This is due to the fact that T-Mobile will no longer support the 3G signal, and in the case of phones that do not support VoLTE, voice calls or sending SMS messages via Google Fi phones used a 3G connection. However, Google provides an interesting discount for customers. If, by the end of December this year, customers purchase a VoLTE-enabled phone and activate it in the Google Fi service, the same Google undertakes to provide compensation of 100$ to customers.