I have had my Navionics app on my Android for probably three years. While it's possible it asked to update itself I don't remember it happening, i.e., pretty sure it's the same map I bought it with.

Which to me is not a problem. I use it as a back up to the boat's chart plotter and for trip planning with family/friends ahead of the charter. While I'm sure there are errors I have not noticed where they might be.

How are you planning on using the app that you are concerned about getting the very latest maps?