The update states that starting April 26th, unless you specifically opt out, you will be enrolled in the program.
We’ve heard many say they prefer more relevant ads so we’re defaulting to this setting.T-Mobile Spokesperson
This is going to include every user that came to T-Mobile through the carrier’s merger with Sprint last year. It’s important to note that Sprint had previously required its customers to opt into sharing their data with advertisers rather than having to opt out.
T-Mobile’s move to opt its customers into a program that sells their data to advertisers is at odds with what tech giants like Google and Apple have been doing recently.
You can, however, easily opt out of the program by opening the T-Mobile app and then tapping the ‘More’. Then, go into the ‘Advertising & Analytics’ section. There, you can toggle ‘Use my data to make ads more relevant to me’ off.