22.214.171.124 PidTagMessageClass Property
The PidTagMessageClass property ([MS-OXPROPS] section 2.787) denotes the specific type of the Message object. It determines the set of properties defined for the message, the kind of information the message conveys, and how to handle the message.
All characters in this property MUST be from the ASCII characters 0x20 through 0x7F. It MUST NOT end with a period (ASCII character 0x2E), and its length MUST be greater than zero and less than 256 characters. Furthermore, its length SHOULD be fewer than 128 characters because some operations require extending the value of the PidTagMessageClass property.
Any equality or matching operations performed against the value of this property MUST be case-insensitive.
The value of this property is interpreted in groups of characters separated by periods ("."). Each group specifies a type of object. A message class of "IPM.Note" denotes a standard Message object, and a message class of "Remote.IPM.Note" indicates a header message object.