Frontier's object database is now an outline. You can expand and collapse tables in their own windows. Dragging move works within a single window, between tables. Navigation is the same as using other Frontier outlines. The same table can appear in its own window while expanded in another window.
Fat pages are the new cross-platform file format.
The internal structure of the odb has changed. Frontier 5 for Macintosh can open Frontier 4 objects, but Frontier 4 cannot reliably open Frontier 5 objects, even when exported as 2CLK files. Frontier now supports file-based objects. Window-based objects can now live in the file system instead of the odb. The Save a Copy item changes to Save As.