The introduction of 5G — alongside widespread adoption of 4G LTE-enabled devices — has prompted major players to shut down older networks. Companies relying on older cellular networks, including 3G, CDMA and 2G, to run their remote monitoring and telematics applications will soon start to experience performance issues and reliability drops ahead of widespread network shutdowns.
As 3G support is phased out, companies operating devices that utilize 2G or 3G and are not compatible with 4G LTE...
https://www.freightwaves.com/news/still-relying-on-3g-networks-it-is-time-for-an-upgrade