Elasticsearch 2.3.1, based on Lucene 5.5.0, has been released as a bug fix update, addressing a thread deadlock issue in Shield that could prevent nodes from joining the cluster. This release is available on Elastic Cloud, the Elasticsearch-as-a-service platform, and users of Elasticsearch 2.3.0 with Shield are advised to upgrade. Feedback is encouraged via Twitter or the forum, and any issues can be reported on the GitHub issues page.