Here is the reply I received
At this moment there is no immediate way for us to upgrade in this sense as it depends on the eligibility of each line. Based on your device activation date, it looks like its only been on our account for about 3 months, so it still has a ways to go before its eligible. This could change depending on the kinds of changes Sprint makes to our account or to their network, especially if they were to ever change to the point where the MiFi 8000 can’t reach the network any longer, but at this time we have not been informed of any changes like that.
My guess is this will change next year as TMobile announced it is shutting down Sprints LTE network in mid 2022
