After last week rolling out new Simple Choice Data-Only plans that offer no voice minutes, T-Mobile is now launching a new feature focused on improving voice calls.

T-Mobile today confirmed that it’s rolling out Enhanced Voice Services (EVS), an upgrade to voice calling that offers better call reliability in weak signal areas for fewer dropped calls. EVS also offers calls that are higher-fidelity than HD Voice thanks to its broader audio frequency range, which should offer more realistic-sounding audio.

EVS works whether you’re on Wi-Fi or LTE, and T-Mobile says that thanks to its “patent-pending deployment,” you’ll get benefits even if you’re talking to someone on a non-EVS phone.

So which phones support EVS? T-Mobile says that its LG G5 supports the feature out of the box, and its Samsung Galaxy S7 and S7 edge were updated to support EVS this week. T-Mo plans on a total of seven more EVS-capable phones by the end of 2016, but it didn’t say which devices those will be.

While not everyone cares about voice calls anymore, a lot of folks do still like to use their smartphones as phones. T-Mobile knows this, which is why its building on its HD Voice and Voice over LTE (VoLTE) rollouts by adding EVS to its devices, too. EVS sounds like a nice upgrade, offering fewer dropped calls and higher-quality voice, so if you’re a T-Mo customer that cares about voice calling, you may want to consider making your next upgrade a device that supports EVS.