elasticsearch/docs/reference/migration/migrate_1_6.asciidoc

[[breaking-changes-1.6]]
== Breaking changes in 1.6

This section discusses the changes that you need to be aware of when migrating
your application from Elasticsearch 1.x to Elasticsearch 1.6.

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=== More Like This API

The More Like This API query has been deprecated and will be removed in 2.0. Instead use the <<query-dsl-mlt-query, More Like This Query>>.

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=== `top_children` query

The `top_children` query has been deprecated and will be removed in 2.0. Instead the `has_child` query should be used.
The `top_children` query isn't always faster than the `has_child` query and the `top_children` query is often inaccurate.
The total hits and any aggregations in the same search request will likely be off.