Before I got ATT service (since beginning of this month), I had T-mobile for less than a year. With T-mobile I was able to use Wi-Fi calling without any issues. It would activate immediately after turning it on and things would just work. For some odd reasons, Wi-Fi calling is not working for me with my ATT service. Not that I need it, but still concerned that when I might need. My account is enabled for Wi-Fi calling, my emergency address is updated and I just do the same thing as I previously did with T-mobile, but nothing happens, no errors, no prompts, just nothing. Also my carrier is current 24.2 I have to admit that I am lazy and been using a restored backup from 5S from Verizon days (that was before my T-mobile service), so not sure if this is the time that I just simply setup my phone from scratch, or is there anything else I could do to check.