Only getting 3G service
i have a T-Mobile phone which is unlocked and i got it fully working with AT&T. Right now I am using a the Stock ROM. What I can't figure out is why I am only getting 3G service when people in my house who have T-Mobile are getting 4G and people in my house with the new iPhones who are also on AT&T are getting LTE service. Does it have to do with the APN settings or is it because I'm using a T-Mobile phone instead of a At&T phone.
Thanks so much in advance,
P.S. I love your videos!
edited: Sorry I forgot to say that I am in the United States.