T-Mobile is forcing users on its older unlimited plans to move to some of its latest options. The carrier confirmed to CNET that starting next week, notices will be sent to T-Mobile users on its older One, Simple Choice, Magenta and Magenta 55 Plus plans, alerting them that starting with their November bill cycles their respective plans will change and their monthly pricing will go up. 

The notices will go out starting Oct. 17, and T-Mobile tells CNET that "there will be an increase of approximately $10 per line with the migration." A spokesperson noted that those who sign up for AutoPay can save $5 per line (on up to eight lines per account). 

T-Mobile recently changed its automatic payment rules to require a linked bank account or debit card as opposed to a credit card, though with the company's troubled history of data breaches consumers may be wary of linking banking information to their accounts. 

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"We're always looking for ways to give our customers more from our services so we're moving a small number who were on older rate plans to newer plans that will deliver them enhanced features," T-Mobile said in a statement. It wasn't immediately clear how many people will be impacted or what a "small number" meant.  

The company adds that those who don't want to have their plan changed will be able to reverse the move, but they'll need to call T-Mobile's Customer Care support line to make that happen. 

The carrier is giving users a period of time to call in and reverse the forced switch, but how long that period will be is unknown at this point. It's also unknown whether customers who go back will be able to stay on their older plans for good or if a reversal simply buys a little more time before they're again compelled to switch.

News of the plan changes first leaked on Reddit, The Mobile Report and on the Tech Life Channel on YouTube. 

According to the leak on Reddit, customers on Simple Choice will be moved to either Magenta or Essentials Select, folks on Magenta or One will move to Go5G, and people on Magenta 55 Plus will be migrated to Go5G 55 Plus. Business users on Simple Choice Business will similarly be switched over to the carrier's Business Unlimited Advanced. 

The forced changes to legacy plans come more than three years after T-Mobile completed its merger with Sprint. One of the promises to get the merger approved by regulators was that the carrier wouldn't raise rates on plans for three years. It's since introduced a Price Lock promise to not raise rates on plans, but that guarantee largely applies only to its newer plans, from the last two years. 

As part of its Price Lock page, T-Mobile does note that customers who are on "eligible plans" from before April 28, 2022, and don't want to switch to a new T-Mobile plan will be able to have the carrier cover "your final month's recurring service charge if we were to raise prices and you choose to leave." 

People looking to take advantage of that offer need to give the carrier notice "within 60 days."