[[breaking-changes-7.3]]
== Breaking changes in 7.3
++++
<titleabbrev>7.3</titleabbrev>
++++

This section discusses the changes that you need to be aware of when migrating
your application to Elasticsearch 7.3.

See also <<release-highlights>> and <<es-release-notes>>.

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

//tag::notable-breaking-changes[]
[discrete]
[[breaking_73_mapping_changes]]
=== Mapping changes
`dense_vector` field now requires `dims` parameter, specifying the number of
dimensions for document and query vectors for this field.

[discrete]
==== Defining multi-fields within multi-fields

Previously, it was possible to define a multi-field within a multi-field.
Defining chained multi-fields is now deprecated and will no longer be supported
in 8.0. To resolve the issue, all instances of `fields` that occur within a
`fields` block should be removed from the mappings, either by flattening the
chained `fields` blocks into a single level, or by switching to `copy_to` if
appropriate.

[discrete]
[[breaking_73_plugin_changes]]
=== Plugins changes

[discrete]
==== IndexStorePlugin changes

IndexStore and DirectoryService have been replaced by a stateless and simple
DirectoryFactory interface to create custom Lucene directory instances per shard.


[discrete]
[[breaking_73_search_changes]]
=== Search changes

[discrete]
==== Deprecation of queries

The `common` query has been deprecated. The same functionality can be achieved
by the `match` query if the total number of hits is not tracked.

[discrete]
===== Deprecation of query parameters

The `cutoff_frequency` parameter has been deprecated for `match` and `multi_match`
queries. The same functionality can be achieved without any configuration provided
that the total number of hits is not tracked.

[discrete]
[[breaking_73_ccr_changes]]
=== CCR changes

[discrete]
==== Directly modifying aliases of follower indices is no longer allowed

Aliases are now replicated to a follower from its leader, so directly modifying
aliases on follower indices is no longer allowed.
// end::notable-breaking-changes[]