5G replaced 4G, the fourth mobile internet generation. The progress of mobile internet began with 1G in 1979, the first mobile network. 2G, the first mobile network that used digital technology, followed in 1991. Next was 3G in 2002, which made data transfer speeds much faster at three megabits per second (Mbps). This was followed by 4G in 2009, which increased speeds to as much as 100 Mbps. Finally, 5G came in 2018 with theoretical speeds up to 20 Gbps.