elasticsearch/docs/reference/migration/migrate_8_0/mappings.asciidoc

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[[breaking_80_mappings_changes]]
=== Mapping changes

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

//tag::notable-breaking-changes[]

// end::notable-breaking-changes[]

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==== Limiting the number of completion contexts

The number of completion contexts within a single completion field
has been limited to 10.

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==== Removal of types

The typed REST endpoints of the Put Mapping, Get Mapping and Get Field mapping
APIs have been removed in favour of their typeless REST endpoints, since indexes
no longer contain types, these typed endpoints are obsolete.

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==== Defining multi-fields within multi-fields

Previously, it was possible to define a multi-field within a multi-field.
Defining chained multi-fields was deprecated in 7.3 and is now no longer
supported. To migrate the mappings, all instances of `fields` that occur within
a `fields` block should be removed, either by flattening the chained `fields`
blocks into a single level, or by switching to `copy_to` if appropriate.

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[[fieldnames-enabling]]
==== Disallow use of the `enabled` setting on the  `_field_names` field

The setting has been deprecated with 7.5 and is no longer supported on new indices.
Mappings for older indices will continue to work but emit a deprecation warning.
The `enabled` setting for `_field_names` should be removed from templates and mappings. 
Disabling _field_names is not necessary because it no longer carries a large index overhead.