Despite the example of it on the documentation for updates...Don't see it on mine either.
While that would make sense, mine showed up for at least the first year even though I was on the latest update when I purchased the vehicle (I had the dealer install it since it added Carplay to the vehicle).I remember reading somewhere that the button only shows up if there is an update available for your specific vehicle. The button not showing up is supposed to indicate that no update is available/needed. That being said, mapnsoft.com appears to have an update available for my 2018, but the My Hyundai site does not show one.