Open Atrium 2 adds several new core concepts that make it even more flexible for your organization. First, rather than seeing a set of "tabs" for each App (Discussion, Files, Calendar, etc.) a Group Owner can create custom "Section" pages and place any combination of available "widgets" on each page. You can use the default section page layouts to recreate the OA 1.x tab pages, or you can creatively combine various elements into your own section page layouts.