AT&T is shutting down its 3G networks as part of a greater effort to re-use the spectrum for 4G and 5G — newer standards that are more efficient than 3G. The shutdown will impact people still using 3G Kindles, 3G flip phones, the iPhone 5 and older models as well as various Android phones. It will also affect home alarm systems and medical devices such as fall detectors and roadside assistance systems like OnStar will need to be updated or replaced, too. The network launched in 2002 and became the driving force behind the early App Store boom around the end of that decade. Verizon said 99% of its customers have already upgraded to 4G LTE or 5G networks, less than 1% of their mobile data runs on 3G . . .