StatusAll: Return results where the message status has changed since the date/time specified - but limited to the start of the current day. StatusPlus: Return results where the message status has changed since the date/time specified - but limited to the start of the previous day. All: Return results for all messages submitted since the time specified. Not efficient and not recommended. MessageId: Return results for the MessageId specified, remembering that this was the returned element 'MessageId', not necessarily the MessageId you requested. The least efficient method and not recommended.