Elasticsearch 6 significantly changes how data is indexed compared to previous versions. Indexes upgraded from Elasticsearch 5 to 6 will maintain backwards compatibility with the previous index structure,
but any indexes created in Elasticsearch 6 can only be accessed using the new "single type" approach. Add-ons that depend on Elasticsearch or extend XenForo Enhanced Search may need to be modified to take these changes into account.
Please ensure you test before upgrading to or installing Elasticsearch 6.
XenForo Enhanced Search requires Elasticsearch and XenForo 1.3.0 or later.
Installation, Upgrading and Configuration
Please see our XenForo Enhanced Search manual page for more information.