I've got two NAV II controllers and one is on Version 10 something and the other way back on version 5.23.  I'd like to update both my FMX displays to version 10.13.  I've done display updates numerous times but never a NAV update.  I've downloaded AP Toolbox and have a USB to serial cable.  Can anyone document the NAV update process?  Things to be aware of?  Can I skip versions?