Is it possible to edit titles or menus in Studio that were created in previous Studio versions

Yes, you can use and edit titles or menus in Studio 16 and Avid Studio that were created in previous Studio versions.

If the previous version (Studio 14/15 for example) was already installed when Studio 16 and Avid Studio was installed, the titles or menus should be stored here:

C:\Users\Public\Documents\Pinnacle\Content\Titles\My Titles (Menus\My Menus, etc.)

If Studio 16 and Avid Studio was installed on the system first, the titles or menus should be stored here:

Avid Studio Users - C:\Users\Public\Documents\Avid\Content\Titles\My Titles (Menus\My Menus, etc.)
Pinnacle Studio 16.0.0.75- C:\Users\Public\Documents\Avid\Content\Titles\My Titles (Menus\My Menus, etc.)
Pinnacle Studio 16.0.1.98 or higher Users - C:\Users\Public\Documents\Pinnacle\Content\Titles\My Titles (Menus\My Menus, etc.)

Note: Put the background in the "Backgrounds" or "Backgrounds 16x9" folder and buttons in the "Buttons" folder

The Titles or Menus will then be detected, converted, and added to the Library.