Explained: AT&T and T-Mobile VoLTE phone cutoffs

4G network icon

Credit: Robert Triggs / Android Authority

Both AT&T and T-Mobile are bringing support for devices without Voice over LTE (VoLTE) and HD Voice to a close in the coming months. Older smartphones that rely on 3G networks for calls and don’t support high-quality voice calls over 4G LTE will cease to work on these networks.

These US carriers are phasing out old 3G voice calling technologies as they focus on current 4G LTE networks and the continued rollout of 5G over the coming years. This allows them to increase capacity for newer networks, by dropping legacy technologies that are less commonly used. The drawback for consumers is those older smartphones, and even a few newer ones, will no longer work on AT&T and T-Mobile networks after they make the switch.

What is VoLTE/HD Voice and how does this all work?

Making voice calls is intrinsically linked to the capabilities of your mobile network and device. The quality and features available for voice calls depends on the type of network you’re connected to, such as 2G, 3G, or 4G, as well as the capabilities of your smartphone. VoLTE and HD Voice are two modern protocols used for making wireless calls, taking advantage of the up to three times higher bandwidth of 4G LTE for much clearer, higher quality calls, compared to older networks. New devices make use of superior VoLTE and HD Voice, while older devices still use existing 3G networks.

As 3G is switched off, you need VoLTE or HD Voice support to make calls on 4G networks.

VoLTE allows for the simultaneous use of voice and data during calls, so you can look something up online while still on a call. It also supports 6-way conference calls. The move to 4G also provides lower latency, reducing those infuriating instances where you end up talking over each other due to the call delay. Likewise, the HD Voice codec offers the same benefits by leveraging 4G LTE networks, but can also extend capabilities on older networks.

What’s important is that VoLTE and HD Voice use 4G LTE to offer better quality calls compared to 3G and 2G equivalents. Modern smartphones almost universally support these technologies, so there’s little reason to continue to support the inferior, aging standards. Especially as carriers are looking to free up old spectrum for use with new 5G networks.

Calls on 3G networks still exist, in part, as a fallback for older devices and to ensure calls can be made in areas without 4G coverage. However, both of these are increasingly less important. All modern smartphones support VoLTE calls and 4G LTE network coverage is increasingly comprehensive, even at network edges. In a nutshell, there’s diminishing reasons to keep supporting old, inferior 3G calls and networks for many carriers. We can probably expect more carriers around the world to make the switch in the coming years as well.

Read more: How Enhanced HD Voice makes your calls crisp and clear

The trade-off is that the few devices that don’t support VoLTE and HD Voice won’t be able to fall back to 3G and 2G to make calls once these networking technologies are switched off. They’ll essentially just become 4G data devices.

Samsung Galaxy Z Flip Duo call bottom half

Duo split bottom

When does 3G voice support end?

T-Mobile customers can no longer activate new devices without VoLTE capabilities. Thie rule came into force on August 4th 2020. Current T-Mobile and Metro by T-Mobile customers can no longer use phones that don’t support VoLTE starting from January 2021. The company will send out text messages to affected customers soon, if they haven’t done so already.

4G-only calling goes live by Jan 2021 for T-Mobile and Feb 2020 for AT&T.

AT&T is giving its customers much more of a heads up. The carrier plans to drop non-HD-Voice devices from February 2022. Emails have already started arriving to inform customers that their phones are won’t be compatible with the network in the future. However, AT&T hasn’t handed the transition particularly well. Having failed to inform consumers of the date properly and also sending messages out to subscribers who own HD Voice capable handsets.

How can I tell if my device is supported?

Both carriers are sending out messages to customers using devices that won’t be supported. So if you don’t receive a message, you can probably assume your smartphone will keep on working just fine. If you want to be absolutely sure, there are a couple of ways to doublecheck compatibility yourself.

Even though VoLTE and HD Voice has been supported in smartphone modems since 2013 and 2014 respectively, don’t take this as a given that your device will continue to work. AT&T’s HD Voice implementation only works with certain handsets. You can find the list of supported smartphones as well as unlocked models below.

As for T-Mobile, the carrier says that all of the handsets it has sold in the last five years will continue to work come January 2021. In lieu of a device list, you can use T-Mobile’s compatibility checker to see your device works with the network. It just requires you to input your phone’s IMEI number, which you can find in the settings menu under About Phone.

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