The PR_CHANGE_KEY property contains a binary number that uniquely identifies the message or folder version.
| Header file: | EDKMDB.H |
| Applies to: | Message and public folder objects (information store objects) |
| Identifier: | 0x65e2 |
| Property type: | PT_BINARY |
| Access: | Read-only |
The PR_CHANGE_KEY property is used primarily by the incremental change synchronization (ICS) interface. This property is assigned to an object that has undergone a change by the store in which the object was modified. This property travels with the object and is only updated when the object is next changed.
For Microsoft Exchange Server, the PR_CHANGE_KEY property is 22 bytes in length, which includes the store GUID (16 bytes) followed by a 6-byte number that is unique to the store.
Synchronizer implementers must format the PR_SOURCE_KEY as a minimum of 17 bytes in length, including a GUID and a unique binary number that identifies the object within the foreign store.
Two change keys from the same store can be directly compared. In the case of Microsoft Exchange Server, the larger number represents the most recent change.
Note: It is recommended that third-party developers do not use 6 bytes as their unique number.
For more information, see About Incremental Change Synchronization.
IExchangeExportChanges, IExchangeImportContentsChanges, IExchangeImportHierarchyChanges, PR_PARENT_SOURCE_KEY, PR_PREDECESSOR_CHANGE_LIST; PR_SOURCE_KEY