get-calendardiagnosticobjects

This cmdlet is available only in the cloud-based service. Use the Get-CalendarDiagnosticObjects cmdlet to collect a range of calendar logs. The calendar diagnostic logs track important calendar-related event data for each mailbox, and can be used to troubleshoot calendar issues that occur in mailboxes. The logs track all calendar items and meeting messages. For information about the parameter sets in the Syntax section below, see Exchange cmdlet syntax (https://technet.microsoft.com/library/bb123552.aspx).

https://docs.microsoft.com/en-us/powershell/module/exchange/mailboxes/get-calendardiagnosticobjects?view=exchange-ps

https://blogs.technet.microsoft.com/messagingninjas/2016/07/06/figuring-out-which-client-was-used-by-the-sender-to-send-an-email/

Here are the various Client Types and their meaning.