upgrade nokia 521 on t mobile

[bobbee25]

Would like to upgrade my wifes nokia 521, larger screen etc. What phones work with tmobile, we use their prepaid. What does it mean locked an unlocked ?

 

[hang-the-9]

https://www.cnet.com/news/unlocked-phones-vs-locked-phones-why-you-should-care/

There is a large number of phones that will work on T-Mobile, almost any phone that works with GSM should activate with T-Mobile. Or just contact them or check on their website for more info.