The feature described here -- https://www.drupal.org/project/mail_safety/issues/2894814 → -- and added to Drupal 7 release does not exist in more recent versions.
"After enabling saving to the dashboard, mails will stack up and are never cleaned up. This can cause an the database to be overloaded with old mails. Feature request to add a periodic cron clean up, based on the settings the user can provide."
Add same functionality to most recent release
Active
2.0
Code
Currently I have this in a cron job:
$now = new DrupalDateTime('-90 days');
$delete = \Drupal::database()->delete('mail_safety_dashboard');
$delete->condition('sent', $now->getTimestamp(), '<');
$delete->execute();
We could set this up in a container with dependency injection, and add a config to set the retention time.