Elasticsearch 1.5.1 Released

On April 9, 2015, the release of Elasticsearch 1.5.1 was announced, providing a stable version based on Lucene 4.10.4, which includes important bug fixes and improvements. A key update addresses the speed of allocating a shard to a new node during recovery by enabling merges on the target shard, thereby preventing the accumulation of small segments and enhancing recovery speed. Additional fixes involve improving the handling of repositories with numerous snapshots and forcing a refresh when deletes fill up the version map. Several experimental inner hits feature issues were also resolved. Notably, rivers have been deprecated in this version, and users are encouraged to download, test, and provide feedback on the release.