If the component is an evaluation version, it returns a message containing the expiration date. If the component is not an evaluation version, it returns a message saying this is a functional version.
[C#]
EmailMessage msg = new EmailMessage("Mail1.MyCompany.com");
Console.WriteLine( msg.ExpirationDate() );
[Visual Basic]
Dim msg As New EmailMessage("Mail1.MyCompany.com")
Console.WriteLine(msg.ExpirationDate())