iPhone 7 Plus under Apple Upgrade Program / changing carriers
I am thinking in buy my Iphone 7 + under this Apple upgrade program to take advantage of their Installment plan (pay spread) and to be out of these carriers contracts. Here is my situation:
I have my business phone line (paid by my company) under T- Mobile. I have my personal line with AT&T. I would like to buy a new Iphone 7+ with all these info I said, and instead of use with my AT&T line ( is being used by my son), have it working with my T-mobile.
So, here is my question: If I buy at apple.com, as AT&T, using my AT&T info to get it, when it comes, can I simply insert my T-mobile sim card ?, or I need to activate under AT&T and then request Apple to unlock ?
As I said, this is just because I won't pay full price for a unlocked phone upfront, and I want to have upgrade program+ Apple care, etc, as it is offered to AT&T, Verizon and Sprint.