Version 6.5.3 of the Elastic Stack was released on December 11, 2018, addressing notable issues in Beats and Kibana. Key bug fixes include the restoration of the "group by terms" functionality in Kibana's Time Series Visual Builder, which was affected by CSS styling changes introduced in version 6.5, and the correction of rfc3164 syslog parsing for December in Filebeat, which was due to a typo in the log parsing code. Users are advised to upgrade to this latest version for improved performance, and further details can be found in the release notes for Kibana, Elasticsearch, and Beats, noting that there are no changes in Logstash.