We've bumped the major version because of a breaking change in the upgrade procedure. Upgrading to this version will require full cluster downtime. Before upgrading, please see our guide to [upgrading to Chef Backend 2](https://docs.chef.io/server/upgrade_server_ha_v2/).

## Enhancements

### Elasticsearch 5

We now ship Elasticsearch 5 by default. This requires a full cluster downtime during the upgrade. Please see the [upgrade instructions](https://docs.chef.io/server/upgrade_server_ha_v2/) for this release for details.

### Improved Health Checking for demoted leaders

During demotion, the management service leaderl stops PostgreSQL. Previously this would result in all health checks for PostgreSQL failing, meaning the node could not resume leadership. Now, we track whether PostgreSQL is only down because of action taken by leaderl, allowing demoted leades to resume leadership in some cases.

## Bug Fixes

### EPMD fails on certain IPv6 configurations

This build should fix issues related to the Erlang Port Mapper Daemon (EMPD) failing to start in some EPMD configurations.

## Security Fixes

### Java 8u144

Updated the version of Java to 8u144 to address CVE-2017-3526.

### Ruby 2.3.5

Update the version of Ruby to 2.3.5 to address multiple CVEs.