Check the
Navionics web site
I don't believe they will update the charts, you need to buy a new chip, but I could be wrong.
I really like my 435, although i'd like a bigger screen, it works very well. Biggest issue I have, it's slow while zooming in and out when you get a lot of detail on the screen. A pain when you're trying to see the bigger picture and then go back to close up.