I have a 3206 XMWX Weather network, a 168 Sounder and a Legend. Go to Garmin's website and sign up on their email/owners update list and they will notify you whenever a software update is available for your unit or charts. They are constantly updating and adding more detail and it has all been free so far.
Go to
www.garmin. com and you should be able to find most info you want.