Elasticsearch 6.x is being deprecated with the intention to remove support in GitLab 13.8.

@JohnMcGuire as per !45619 (comment 435133740) we need to note that ES 6.x is deprecated in the next release (and will be removed in %13.8 ). Can we make sure this gets a release note.

Release notes

Elasticsearch 6.x is being deprecated with the intention to remove support in GitLab 13.8.
Elasticsearch 6.x indices will no longer be compatible with Elasticsearch 8.0 Which will be released in the next few months. All customers using Advanced Search should plan to upgrade to Elasticsearch 7.x or greater before upgrading to GitLab 13.8. If you are currently running GitLab version older than 13.2 Please refer to the Version Requirements for GitLab and Elasticsearch versions.