I currently own a Samsung Galaxy S5, purchased from AT&T. It has what I presume is an AT&T version of the OS with an AT&T boot screen, etc. Software updates are also delivered OTA via AT&T servers. I am considering switching to T-Mobile and was wondering if/how I will receive updates after the switch. Will I still get updates from the AT&T servers, or will I somehow be transferred to T-Mobile's system?