I have some information that might make all of you guys happy.
I was told by Safelink Wireless that VOTLE is a function of BOTH the phone *AND* the sim card.
Basically, if the phone itself is VOLTE compatible but the sim card is not, then the phone will be reported on their system as not compatible, and will ask you to upgrade your phone.
However if a VOLTE compatible SIM is inserted, if the phone does in fact support VOLTE, it will then work. That's because it's provisioned on the carrier via the sim card itself.
If you purchased a sim via the "Buy your own sim" package, e.g. online or from Best Buy, etc, awhile ago, then that sim is not compatible. You simply need to call Tracphone/Safelink and ask to buy a VOLTE compatible SIM (which costs 99 cents). Then when you get it, call their tech department to have them transfer the phone service and phone number to the new SIM.
You can dial the phone's service menu and go to the VOLTE/GPRI menu and if the options are there, then the phone supports it.