Last June, we redesigned the Reports section in the Admin console to make it easier for admins to manage Google Apps and gain insights that help their entire organization run more efficiently. The improved Reports section provides domain highlights, user-level reporting, custom filtering/sorting on data, aggregated domain level reports and new audit streams (Login and Calendar Audit).
Since the launch of the new Reports section, the old UI in admin console has been accessible via the Settings icon. On March 31, 2015, we’ll be removing access to the old Reports UI and shutting it down. All functionality available in the old UI is currently available in the new Reports section.
Source: Google Apps Updates