[[breaking_60_mappings_changes]] === Mapping changes ==== Coercion of boolean fields Previously, Elasticsearch recognized the strings `true`, `false`, `on`, `off`, `yes`, `no`, `0`, `1` as booleans. Elasticsearch 6.0 recognizes only the strings `true` and `false` as booleans and will throw an error otherwise. For backwards compatibility purposes, during the 6.x series the previous coercion rules will continue to work on pre-6.0 indices. This means that you do not need to change affected existing mappings immediately. However, it is not possible to create new indices from existing index templates that violate the strict `boolean` coercion rules. ==== The `_all` meta field is now disabled by default On new mappings, the `_all` meta field that contains a copy of the text from each field is now disabled by default. The `query_string` and `simple_query_string` queries that previously used `_all` to search will now check if `_all` is enabled/disabled and switch to executing the query across all fields if `_all` is disabled. `_all` can no longer be configured for indices created with Elasticsearch version 6.0 or later. ==== The `include_in_all` mapping parameter is now disallowed Since the ++_all++ field is now disabled by default and cannot be configured for indices created with Elasticsearch 6.0 or later, the `include_in_all` setting is now disallowed for these indices' mappings. ==== Unrecognized `match_mapping_type` options not silently ignored Previously Elasticsearch would silently ignore any dynamic templates that included a `match_mapping_type` type that was unrecognized. An exception is now thrown on an unrecognized type.