Applies to: Exchange Online | Exchange Server 2007 | Exchange Server 2010 | Exchange Server 2013 | Office 365
The BaseItemId element represents the base class for IDs that represent items in a mailbox. This is an abstract class and therefore will not occur in an instance document.
This element is an abstract base type for item identifiers. This element is not used in Web service calls.
The schema that describes this element is located in the EWS virtual directory of the computer that is running MicrosoftExchange Server 2007 that has the Client Access server role installed.