You can no longer scan the cache for NPCs

[semlar]

Using tooltip:SetHyperlink('unit:Creature:0:0:0:0:' .. npcID) or model:SetCreature(npcID) will now return valid data for units that the client has never seen before.

Calling either function will query the server and the client will cache the information when it becomes available.

This means you can display models or scrape tooltip text for NPCs you haven't seen, but it also means addons like NPCScan will no longer function.