T-Mobile is making a significant change for its subscribers in the United States, including those that own Samsung Galaxy devices. The company has confirmed that it's migrating subscribers from some of its legacy plans to newer plans. Consequently, some subscribers may see a price increase. Migration may impact millions of T-Mobile subscribersT-Mobile has confirmed in a statement to Android Authority that it's retiring “our oldest plans, some of which were built nearly 15 years ago.” These plans were built when T-Mobile's 5G network wasn't fully deployed.The carrier says that this migration would provide subscribers with access to enhanced features. It's also promising a 5-year price guarantee. Some customers won't see their bills being changed, while others will find a “modest adjustment.”It hasn't named the plans that are being phased out, but the report mentions that they may include T-Mobile's Simple Choice, ONE, ONE Plus, and Magenta plans. Grandfathered Sprint plans from the carrier's merger with T-Mobile back in 2020 may also be included.Fortunately, the likely price increases may not be too high. Some subscribers may see a $6 per line increase on voice plans while watch and tablet lines may go up by $3. Those who have 5G Home Internet could see a $6 increase as well. No price increases are likely to be made on free lines.