[discrete]
[[breaking_80_index_setting_changes]]
==== Index setting changes

//NOTE: The notable-breaking-changes tagged regions are re-used in the
//Installation and Upgrade Guide

//tag::notable-breaking-changes[]
[[index-max-adjacency-matrix-filters-removed]]
.The `index.max_adjacency_matrix_filters` index setting has been removed.
[%collapsible]
====
*Details* +
The `index.max_adjacency_matrix_filters` index setting has been removed.
Previously, you could use this setting to configure the maximum number of
filters for the
{ref}/search-aggregations-bucket-adjacency-matrix-aggregation.html[adjacency
matrix aggregation]. The `indices.query.bool.max_clause_count` index setting now
determines the maximum number of filters for the aggregation.

*Impact* +
Discontinue use of the `index.max_adjacency_matrix_filters` index setting.

Requests that include the index setting will return an error. If you upgrade a
cluster with a 7.x index that already contains the setting, {es} will
{ref}/archived-settings.html#archived-index-settings[archive the setting].

Remove the index setting from index and component templates. Attempts to use a
template that contains the setting will fail and return an error. This includes
automated operations, such the {ilm-init} rollover action.
====

.The `index.force_memory_term_dictionary` setting has been removed.
[%collapsible]
====
*Details* +
The `index.force_memory_term_dictionary` setting was introduced in 7.0 as a
temporary measure to allow users to opt-out of the optimization that leaves the
term dictionary on disk when appropriate. This optimization is now mandatory
and the setting is removed.

*Impact* +
Discontinue use of the `index.force_memory_term_dictionary` index setting.
Requests that include this setting will return an error.
====

.The `index.soft_deletes.enabled` setting has been removed.
[%collapsible]
====
*Details* +
Creating indices with soft deletes disabled was deprecated in 7.6 and
is no longer supported in 8.0. The `index.soft_deletes.enabled` setting
can no longer be set to `false`.

*Impact* +
Discontinue use of the `index.soft_deletes.enabled` index setting. Requests that
set `index.soft_deletes.enabled` to `false` will return an error.
====

.The `index.translog.retention.age` and `index.translog.retention.size` settings have been removed.
[%collapsible]
====
*Details* +
Translog retention settings `index.translog.retention.age` and
`index.translog.retention.size` were effectively ignored in 7.4, deprecated in
7.7, and removed in 8.0 in favor of
{ref}/index-modules-history-retention.html[soft deletes].

*Impact* +
Discontinue use of the `index.translog.retention.age` and
`index.translog.retention.size` index settings. Requests that
include these settings will return an error.
====
//end::notable-breaking-changes[]
