New value of the attribute
If single assignment attribute: The new attribute value (null if not set) If multi assignment attribute: Array of the added attribute values If single assignment relation: The ID of the new Building Block (null if not set) If multi assignment relation: Array of the IDs of the added Building Blocks
Persistent name of the attribute that was changed
Old value of the attribute
If single assignment attribute: The removed/old attribute value (null if previously not set) If multi assignment attribute: Array of the removed attribute values If single assignment relation: The ID of the removed Building Block (null if previously not set) If multi assignment relation: Array of the IDs of the removed Building Blocks
A Change of relations/attributes of a BB