How many have I missed

I've been pretty lax in keeping up with the updates on helix 9 g2 thinking I'm running 1.36 version can someone tell me how many I need to catch up on? Want to put the updated base map on if I am thinking straight I need to get caught up with all the previous ones....with the new website I'm having trouble locating them..thanks

1.640 is the latest version ...
https://www.humminbird.com/support/software-updates

The basemap is a separate download at the bottom of the list under your unit model ...

It's best to load the unit software 1st and then format the SD card and load the basemap separate ...

Rickie