convert 3g to 4g mifi without losing unlimited Verizon data?

3g and 4g are two different contracts. Yes you can buy a new 4g device and keep your 3g unlimited plan... only problem is your new device will not work on 3g. No they won't give you an unlimited 4g plan just because you buy your device out of network.

Our only hope is that to speed the elimination of 3g they offer old existing customers a transition window. We average 50gb per month on 3g and another 50gb on 4g monthly.