Upgrade Notes:

• Upgrading from 0.18 requires issuing a full flush of all the indices in the cluster (curl host:9200/_flush) before shutting down the cluster, with no indexing operations happening after the flush.
• The local gateway state structure has changed, a backup of the state files is created when upgrading, they can then be used to downgrade back to 0.18. Don’t downgrade without using them.

New features:

• Upgrade to Lucene 3.6 (#1862)

Enhancements:

• Upgrade to Netty 3.4.1 (#1863)
• Better handling of fields that have . in their name when doing property based navigation (#1875)
• Upgrade to Netty 3.4.1.Final (#1878)
• Bulk API: Allow to control if its compressed or not using action.bulk.compress (defaults to true which is current behavior) (#1850)
• Date Histogram Facet: Add quarter as an interval (#1884)
• Node Stats: Add timestamp per node stats element (#1851)

Bug fixes:

• Relocation of shards causes bulk indexing client to hang (#1839)
• Setting index.auto_expand_replicas in the elasticsearch config file does not apply (#1852)
• XContentBuilder throws NPE on null Boolean (#1853)
• On recovery (startup), the recovery translog file handle is not properly closed (#1866)
• NullPointerException in geo_distance_range without to (#1865)
• JDK 7 requires minimum of 256k stack size, update scripts to set it (#1892)
• When a node disconnects from the cluster (not enough master nodes, or a client node) and rejoins it might not update its internal routing table (#1896)
• Highlighting: Using “plain” (non term vector) highlighting with custom score within a filtered query fails to highlight (#1894)
• Translog: Buffering translog does not write directly to the file channel but to RAF, which causes problems reading from the channel on windows (#1887)