Some time ago my customer bought licenses from the "traditional model" (Base + Apex) and they work fine for older versions (up to 2.7). There is another license tier Plus which wasn't bought because we don't need that functionality. However with version 3.0 Cisco moves to "Smart licensing" and changed whole licensing mode.
Here is the thing. We need functionality from "Premier" tier but according to the information from TAC we can't migrate to Premier without Plus licenses. I raised ticket to the TAC regarding licensing and they just refused possibility of the licensing migration even though we have most advanced licenses on board which is strange for me.