The docs say that the default for this feature flag is false and the release notes say it's being transitioned to true in 8.0

https://github.com/mongodb/mongoid/blob/master/docs/reference/configuration.txt#L401

We decided to introduce this feature flag in 8.0, so it should default to the 7.x behavior which would be false. Correct this and add a note to the release notes directing to the documentation.