The following table summarizes the different ranges for property identifiers, describing the owner for the properties in each range.
| Identifier range |
Description |
| 0000 |
Reserved by MAPI for the special value PR_NULL. |
| 0001 - 0BFF |
Message envelope properties defined by MAPI. |
| 0C00 - 0DFF |
Recipient properties defined by MAPI. |
| 0E00 - 0FFF |
Non-transmittable message properties defined by MAPI. |
| 1000 - 2FFF |
Message content properties defined by MAPI. |
| 3000 - 3FFF |
Properties for objects other than messages and recipients defined by MAPI. |
| 4000 - 57FF |
Message envelope properties defined by transport providers. |
| 5800 - 5FFF |
Recipient properties defined by transport and address book providers. |
| 6000 - 65FF |
Non-transmittable message properties defined by clients. |
| 6600 - 67FF |
Non-transmittable properties defined by a service provider. These properties can be visible or invisible to users. |
| 6800 - 7BFF |
Message content properties for custom message classes defined by creators of those classes. |
| 7C00 - 7FFF |
Non-transmittable properties for custom message classes defined by creators of those classes. |
| 8000 - FFFE |
Properties defined by clients and occasionally service providers that are identified by name through the IMAPIProp::GetNamesFromIDs and IMAPIProp::GetIDsFromNames methods. |
| FFFF |
Reserved by MAPI for the special error value PROP_ID_INVALID. |
The range between 3000 and 3FFF is reserved for properties that are not related to either messages or recipients. MAPI divides this range into sub-ranges by types of object; the following table shows this further breakdown.