PropertyHandle :: GetRefModCount - Get collection update count

The function returns an internal modification count for a collection. This allows checking whether the collection has been updated by another user or application by adding or deleting instances from the collection, since each update will increase the modification count stored in the database.

Since the modification count is rotating (starting again with 1 after reaching 255) this is not a save indication. Thus, it is suggested to use server event handler for reacting on changes.