The sun is setting on 3G networks. Credit: Ted/Flickr, CC BY-NC On February 22, 2022, AT&T began shutting down its 3G cellular network. T-Mobile is scheduled to shut it down on July 1, 2022, and Verizon is scheduled to follow suit on December 31, 2022. The vast majority of mobile phones in service operate on 4G/LTE networks and the world has started the transition to 5G, but as many as 10 million…