*   Ensure mail gem is eager autoloaded when eager load is true to prevent thread deadlocks.

    *Samuel Cochran*

*   Perform email jobs in `assert_emails`.

    *Gannon McGibbon*

*   Rails 6 requires Ruby 2.4.1 or newer.

    *Jeremy Daer*


Please check [5-2-stable](https://github.com/rails/rails/blob/5-2-stable/actionmailer/CHANGELOG.md) for previous changes.