Based on this can we first Upgrade to 2018.2 from 10.5 and later add user based license and change users role. Later delete core based licensing model? do we still need to deactivate core based license or simply the key can be deleted? If not suggest us the best way of doing it, Currently we are on 10.5 we want to upgrade to 2018.2 and also change license model to user based.
Below is a link to another forum posting. Be sure to look at the entry by Carisa Chang (the 4th reply in), believe it will help clear up some of your questions