AT&T officially shut down its 2G wireless network on January 1, 2017. This means that any device that only supports AT&T’s 2G network, like the first iPhone, can no longer get service on AT&T.
As for why it decided to shut down its 2G network, AT&T explains that the move will “help support the massive growth of mobile internet usage and free up spectrum for newer technologies.” In the coming months, AT&T plans to repurpose its 2G spectrum for 4G LTE use.
AT&T’s decision to shut down its 2G network probably won’t affect most customers, as they’ve moved on to smartphones that run on AT&T’s 3G and 4G networks. That said, the shutdown will affect all of the connected devices that were running on AT&T’s 2G network. AT&T has been warning its customers about the 2G shutdown since 2012, but there are still likely to be some folks that are frustrated by the decision if they’re forced to make changes to their setups.