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It seems like WiFi calling will work on all iPhones whether bought from Vodafone or not. But the other Android phones on the list of compliant phones have to be bought from Vodafone. I have tried a Motorola G7 Power - not on the list and doesn't work however I try the methodology or hacks. So bought a Sony L4 - it's on the list - but you can't just buy a phone alone from Voda so got one from Amazon. It doesn't work whatever way you try. So do none of the Android phones work with Wi-Fi Calling if you don't have a phone contract? Is iPhone the only option I can take?
Are far as I am aware, that is correct @ChrisDowning. In order for the Wi-Fi calling feature to work on our network, the device would need to have been purchased directly from us. We wouldn't be able to guarantee the same on a phone purchased from third parties unfortunately.