The quick answer

• Calls: yes on AT&T and T-Mobile; no on Verizon
• Software: KaiOS 2.5, with WhatsApp and Google Maps (limited)
• Check the model number under the battery: TA-1324 is the US version
• Import versions often fail on US networks

Calls after the 3G shutdown

The US version (TA-1324) is sold unlocked and supports VoLTE on AT&T, T-Mobile and the prepaid brands that use them, such as Cricket, Metro, Mint and Tracfone. It doesn't work on Verizon or Verizon-based brands like Visible. International versions often lack the right bands.

How to check yours

1. Find the IMEI: dial *#06#, or look in the phone's settings or under the battery.
2. Enter it in your carrier's compatibility checker. Every major carrier and most prepaid brands have one.
3. If it isn't supported, it's usually missing approval for VoLTE (calls over 4G), which every US phone now needs.

Who it still works for

A good basic phone on T-Mobile or AT&T. On Verizon, pick a phone Verizon approves instead.

If you're replacing it

If you want to stay with a flip phone, the Nokia 2780 Flip and Kyocera DuraXV Extreme+ are current models with VoLTE. A basic phone pairs well with a small plan: Tello and US Mobile both have plans under $10 a month for talk and text.