Hi Dave,
From what I gathered there will be only one of those enabled. Which is, on
the list, 'Tabbed'. The others will remain as experimental.
This means that for individual users after either a fresh install, or an
upgrade, the old standard toolbars will be selected as the default
interface, but now every user will have the option to make the Tabbed
Notebook bar their default interface.
For institutional users it can be a bit different. In many of these cases
an network administrator handles installs and updates and could set the new
Tabbed interface for all users. Here a new hire after the change may not
even realize the old standard toolbars are available.
So, my first thought about handling it in 6.2 might be to go the route of
yet another appendix.
For inst