anchor.diff:  // TEST[setup:stackoverflow]
   
   [float]
  +[[breaking_66_setting_changes]]
   === Settings changes
   
   [float]
  
positive.code: `xpack.notification.slack.account.<id>.secure_url`
  
  [float]
  === Mappings changes
  
  [float]
  
negative.code: This section discusses the changes that you need to be aware of when migrating
  your application to Elasticsearch 6.6.
  
  * <<breaking_66_ml_changes>>
  * <<breaking_66_mapping_changes>>
  * <<breaking_66_search_changes>>
  * <<breaking_66_setting_changes>>
  
  See also <<release-highlights>> and <<es-release-notes>>.
  
  