Originally Posted by dragonslayer95
From my understanding to keep your grandfathered unlimited data, can't upgrade without paying full retail or you'll be forced go with a limited plan seeing as how it's resetting your plan.
Sent From My HTC Evo 3D Using TapaTalk 2
you are exactly correct I just upgraded 2 days ago and that is exactly how it works. You must pay full retail for phone to keep the unlimited data.