https://arstechnica.com/information-technology/2018/06/new-t-mobile-upgrade-may-boost-your-coverage-if-you-have-the-right-phone/

It's been a little more than a year since T-Mobile USA bought enough 600MHz spectrum licenses to cover the entire country, and the carrier has now activated the spectrum band in more than 900 cities and towns in 32 states. In 120 of those cities and towns, it's the first time T-Mobile has offered LTE coverage, the company said in an announcement yesterday.