https://www.cnet.com/news/super-bowl-2019-are-the-wireless-networks-up-to-snuff/

Sprint has upgraded cell towers with its Massive MIMO beam-forming technology ahead of the 2019 Super Bowl game in Atlanta. 

Because 5G builds on 4G foundational technologies, carriers will be able to reuse this gear when it's time to light up the next wireless generation simply by upgrading the software.