Where can I find the most current user guide and support documentation for KanBo?
You can see a user guide for the most current version of KanBo here - KanBo User Quick Guide.
All guides and documentation can be found here:
User Guides/Feature Index: http://community.kanboapp.com/forums/11-feature-index/
Here an example how things are explained: http://community.kanboapp.com/forums/11-feature-index/categories/129-card/topics/
Or in detail: http://community.kanboapp.com/topics/605-collapse-elements-lists/