Elasticsearch 2.0.0-rc1, based on Lucene 5.2.1, has been released as the final release candidate before the general availability (GA) of Elasticsearch 2.0, and is intended solely for testing purposes, emphasizing that it should not be deployed in production. This release candidate, which is not compatible with previous beta versions, focuses primarily on minor bug fixes and optimizations, including the points_only optimization for geo-shape fields and a new caching interface in the Shield plugin. The announcement encourages extensive testing to identify and resolve any issues before the GA release, providing links to download the release candidate and access change logs and documentation. Additionally, the Elasticsearch Migration Plugin is available to help users prepare their indices and mappings for compatibility with Elasticsearch 2.0. Feedback is encouraged via Twitter, forums, or GitHub to expedite the GA release process.