If you bought outright you'd have zero issues with doing an ESN swap. I'm unsure how getting a 2yr agreement for phone discount will affect your plan. I say that because some things have changed and you mentioned an older plan. Chances are nothing will change for you.
I however discovered/remembered if I upgrade a member on my family plan their access charge to my plan goes from $15 to $40 a month. Crazy talk.... They wanna charge me More to do a 2 year agreement. For those on the iPhone for life plan it really seems like they want to make us pay for the phone outright regardless because on those plans if you do a 2 year agreement you're charged an extra $25 which is a fixed rate for everyone and as far as I know that charge will stay on there even after the agreement is up. Might as well do easy pay or lease.
I however discovered/remembered if I upgrade a member on my family plan their access charge to my plan goes from $15 to $40 a month. Crazy talk.... They wanna charge me More to do a 2 year agreement. For those on the iPhone for life plan it really seems like they want to make us pay for the phone outright regardless because on those plans if you do a 2 year agreement you're charged an extra $25 which is a fixed rate for everyone and as far as I know that charge will stay on there even after the agreement is up. Might as well do easy pay or lease.