T-Mobile and Sprint officially became one company this year, but Sprint’s previous network still exists as a separate entity. T-Mobile customers had the opportunity to roam Sprint’s cell tower back in September (with the right devices, anyway), and if the latest news is correct, the older network can only last for another year.

T-Mobile has reportedly started sending out alerts to its business customers, saying that the company will completely shut down Sprint’s CDMA network “January 1, 2022 or so.” Devices that support Sprint’s LTE connection will continue to operate after that date, but only CDMA phones will not be able to connect. T-Mobile will no longer activate CDMA-only devices after January 1, 2021, so if you feel nostalgic and want to put your SIM card in an old phone, you only have a few days to switch.

It is worth noting that the source specifically refers to corporate customers, so the deadlines for closure may end up being different for regular T-Mobile subscribers. T-Mobile previously said it would shut down 3G access on its own network by January 1, 2021, and shut down devices that do not support Voice over LTE.