September 24, 2018 (reveal) October 8, 2018 (official)
T-Mobile first announced its intent to buy and merge with MetroPCS on October 4, 2012. The move was completed on May 1, 2013, when they were both integrated into a combined T-Mobile US, Inc., and started trading under the TMUS stock symbol on the Nasdaq, as it saw a dramatic increase in prepaid subscribers combined.
On September 24, 2018, T-Mobile announced that it would rebrand MetroPCS as Metro by T-Mobile. The new name officially took effect 2 weeks later.
As of December 2021, this logo still appears on its website's chat function, as well as the default homepage on Metro-branded devices and some stores, as they are gradually being updated to the current logo.