T-Mobile will wait a while longer to shut down Sprint's 3G network. The Verge reports T-Mobile has delayed the CDMA network shutdown from January 1st, 2022 to March 31st of that year. The carrier pinned the delay on "partners" who hadn't "followed through" on helping their customers transition to newer network technology.
This would supposedly give partners "every opportunity" to fulfill their obligations. "There should be no more room for excuses," T-Mobile said.
The explanation appears to be a not-so-subtle attempt to pin the blame on Dish. The satellite TV provider bought Boost Mobile from T-Mobile in July 2020 and planned to use Sprint's legacy network until it could move Boost customers to its 5G service. Dish argued this didn't give it enough time to migrate its customers, and accused T-Mobile of anti-competitive behavior meant to push Boost exiles to T-Mobile.
This may be a response to both Dish's original accusation and the ensuing fallout. The Justice Department told Dish and T-Mobile in July that it had serious concerns about the Sprint network shutdown, asking the two companies to do whatever was necessary to lessen the blow. The delay might address those worries and reduce the chances of more serious government scrutiny.
A delayed shutdown still isn't ideal. T-Mobile expects to shutter Sprint's LTE network on June 30th, 2022. This leaves a three-month window where Boost customers might have LTE access, but nothing else. While you'll probably have made a decision by the March cutoff if you're a customer, this won't be a very gradual shift for some users — they'll have just a short period of limited Boost service before they have to embrace 5G.