Flag for a modified meeting with Exchange Web Services

I trying to find a way to determine if meeting details have changed so I can update the records of it in a database that is used to display the details for the meetings on a web site.

I k开发者_如何学运维now there is Appointment.LastModifiedTime but that also changes when a response is returned. I want something that will change only if there was an update to the meeting details.

I've seen Appointment.IsUnmodified and tested it with a new meeting but it still returned false.

Does anyone know of a reliable way to check this?

On a side note, is there any id associated with an item that I can use as a reference in the db? I've been using itemID, but i read that under certain circumstances that will change. Is that true?

You can store the ChangeKey along with the UniqueId in the database.