Summary

From Jira 8.4.0 (batchers-1.3.1.jar) below message are added in footer.

Jira is improving email notifications, share your feedback!
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There is a way to remove survey from footer by editing "templates/email/batch/html/footer.vm" in batchers-x.x.x.jar but need to update every time when user upgrade Jira.

• Customizing email content (batched notifications)
  footer.vm

  <td align="left">
      $i18n.getText('issue.update.batch.mail.footer.survey', [$links.survey])<br>
      $i18n.getText('issue.update.batch.mail.footer.mobile', [$links.androidApp, $links.iOSApp])
  </td>
  

Suggestion

Having other disable option that is not affected by upgrade, for example Enable or Disable GOT FEEDBACK button.