Cellular capable sensors include a pre-provisioned Twilio SIM which the sensors use for initial onboarding and to report power outages. This capability depends on coverage and agreements between Twilio and local carriers. In the United States, the carrier is T-Mobile.

As per this announcement, T-Mobile is shutting down its 2G network April 2nd 2024, but may reduce coverage sooner. T-Mobile has already shut down its 3G network.

The impact is that only sensor model UX-E4C will no longer be capable of using cellular connectivity in the United States.

Sensor models UX-F5C, UX-G5C, UX-G6C, and UXi-G6EC are 2G/3G/4G capable and, therefore, unaffected.

You can view the sensor model on the sensor About section or under Settings -> Sensors and Agents