When I had service with Verizon, there was a parameter in "Settings" under "Connections" on my phone that specifically activated or deactivated wifi calling. No parameter exists in "Settings" now related to wifi calling with Mint Mobile's service [WiFi Talk & Text] . Apparently the option is activated, only on Android phones, using the account management menu. I checked my phone's IMEI number against the list provided by Mint of phones that will support WiFi Talk & Text. My number wasn't on the list, but I enabled the option anyway. Several minutes later I got a notification that my wifi calling was activated.
My only thinking related to checking whether it is working or not was to turn off the switch allowing the use of cellular data. The 4G/LTE symbol dimmed and had a slash through it. I then made a call to my phone and it worked great. So my question is: was this a valid test? Was the call being received using wifi only?
My inclination is to believe that YES it is working although my phone's IMEI number is not on the list. I would like to be sure because this feature is very important to me in considering whether or not Mint Mobile meets my needs. (for anyone curious, I own a Samsung Galaxy S8+ with an IMEI number starting 3597 6108, and it's not on Mint's list which has the first 7 or 8 digits of IMEI numbers of devices that support the WiFi Talk & Text feature)