Applies to: Exchange Online | Exchange Server 2013 | Office 365
The ConversationLastSyncTime element contains the date and time that a conversation was last synchronized. This element must be present when trying to delete all items in a conversation that were received up to the specified time.
The schema that describes this element is located in the IIS virtual directory that hosts Exchange Web Services.This element was introduced in Exchange Server 2010 Service Pack 1 (SP1).