2.2.1.2 PidTagConversationId Property

Type: PtypBinary ([MS-OXCDATA] section 2.11.1)

The PidTagConversationId property<1> ([MS-OXPROPS] section 2.650) is a computed value, derived from other conversation-related properties, that identifies a message as belonging to a specific conversation. This property is computed by the application, server or client. The computed value of the PidTagConversationId property SHOULD be derived from the values of the following properties.

If the value of the PidTagConversationIndexTracking property (section 2.2.1.4) is set to 0x01 (TRUE), and the value of the PidTagConversationIndex property (section 2.2.1.3) is at least 22 bytes long and the first byte of the value of the PidTagConversationIndex property is 0x01, then the value of the PidTagConversationId property MUST be the GUID portion of the PidTagConversationIndex property.

Otherwise, if the PidTagConversationTopic property (section 2.2.1.5) is set, the value of the PidTagConversationId property MUST be computed as follows:

  1. The application MUST use up to 255 of the first nonzero characters of the little-endian UTF-16 representation of the PidTagConversationTopic property.

  2. The application MUST convert the characters to their upper-case forms, mapping "i" to "I" regardless of the user's locale.

  3. The application MUST perform an MD5 hash, as specified in [RFC1321], on the characters and use the resulting 16-byte hash as the value of the PidTagConversationId property.

Otherwise, if none of the above conditions were met, the PidTagConversationId property MUST NOT be set, in which case it will be undefined for the Message object.