Old and New values in change tracking
Change streams currently return only the new version of the documents.
If there were an option that could be set on the collection for the change streams to also return the old version of the document, it would simplify any business logic that requires the old version.
Ability to capture pre-image of the document before change and include both pre- and post-image was released in MongoDB 6.0.
This project is planned for implementation, stay tuned for the upcoming releases.