[float] [[breaking_70_mappings_changes]] === Mapping changes [float] ==== The `_all` meta field is removed The `_all` field deprecated in 6 have now been removed. [float] ==== The `_uid` meta field is removed This field used to index a composite key formed of the `_type` and the `_id`. Now that indices cannot have multiple types, this has been removed in favour of `_id`. [float] ==== The `_default_` mapping is no longer allowed The `_default_` mapping has been deprecated in 6.0 and is now no longer allowed in 7.0. Trying to configure a `_default_` mapping on 7.x indices will result in an error. [float] ==== `index_options` for numeric fields has been removed The `index_options` field for numeric fields has been deprecated in 6 and has now been removed. [float] ==== Limiting the number of `nested` json objects To safeguard against out of memory errors, the number of nested json objects within a single document across all fields has been limited to 10000. This default limit can be changed with the index setting `index.mapping.nested_objects.limit`. [float] ==== The `update_all_types` option has been removed This option is useless now that all indices have at most one type. [float] ==== The `classic` similarity has been removed The `classic` similarity relied on coordination factors for scoring to be good in presence of stopwords in the query. This feature has been removed from Lucene, which means that the `classic` similarity now produces scores of lower quality. It is advised to switch to `BM25` instead, which is widely accepted as a better alternative. [float] ==== Similarities fail when unsupported options are provided An error will now be thrown when unknown configuration options are provided to similarities. Such unknown parameters were ignored before. [float] ==== Changed default `geo_shape` indexing strategy `geo_shape` types now default to using a vector indexing approach based on Lucene's new `LatLonShape` field type. This indexes shapes as a triangular mesh instead of decomposing them into individual grid cells. To index using legacy prefix trees the `tree` parameter must be explicitly set to one of `quadtree` or `geohash`. Note that these strategies are now deprecated and will be removed in a future version. IMPORTANT NOTE: If using timed index creation from templates, the `geo_shape` mapping should also be changed in the template to explicitly define `tree` to one of `geohash` or `quadtree`. This will ensure compatibility with previously created indexes. [float] ==== deprecated `geo_shape` parameters The following type parameters are deprecated for the `geo_shape` field type: `tree`, `precision`, `tree_levels`, `distance_error_pct`, `points_only`, and `strategy`. They will be removed in a future version.