doc: EMSCO_DYNAMIC_MAPPING envvar & upgrade

docs/elasticms-admin/environment-variables.md

@@ -273,6 +273,21 @@ Define the default bulk size for commands such as the `ems:environment:rebuild`
 ```dotenv
 EMSCO_DEFAULT_BULK_SIZE=500
 ``` 
+
+### EMSCO_DYNAMIC_MAPPING
+Define the default [dynamic mapping mode](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic.html#dynamic-parameters) for the elasticsearch managed indexes. Default value: `'false'`.
+
+This parameter has been introduced in version 6.0.0. Prior version were then using the elasticsearch default value `'false'`.
+
+```dotenv
+EMSCO_DEFAULT_BULK_SIZE='false'
+``` 
+Possible values are:
+- `true`: New fields are added to the mapping.
+- `runtime`: New fields are added to the mapping as [runtime fields](https://www.elastic.co/guide/en/elasticsearch/reference/current/runtime.html). These fields are not indexed, and are loaded from _source at query time.
+- `false`: New fields are ignored. These fields will not be indexed or searchable, but will still appear in the _source field of returned hits. These fields will not be added to the mapping, and new fields must be added explicitly.
+- `strict`: If new fields are detected, an exception is thrown and the document is rejected. New fields must be explicitly added to the mapping.
+
 
 ### EMS_BACKEND_URL
 Define the url use by the user to access elasticms (in order to generate links in emails).

docs/upgrade.md

@@ -8,7 +8,7 @@
 
 ## version 6.0.x
 
-## Renamed embed methods in web/skeleton templates
+### Renamed embed methods in web/skeleton templates
 
 All controller methods have lost any trailing `Action`
 
@@ -28,13 +28,21 @@ E.g.:
 } )) }}
 ```
 
-## Routes removed
+### Routes removed
 
 * `template.index` must be replaced by `ems_core_action_index`
 * `template.add` must be replaced by `ems_core_action_add`
 * `template.edit` must be replaced by `ems_core_action_edit`
 * `template.remove` must be replaced by `ems_core_action_delete`
 
+### New dynamic mapping config which change the elasticsearch indexes
+
+Before version 6 it was not possible to define elasticsearch dynamic mapping config. In other words, before version 6, every fields present in a document, that aren't strictly defined in the content type, a mapping was automatically guessed by elasticsearch.
+
+Since version 6 the default dynamic mapping config has changed. New fields are ignored. These fields will not be indexed or searchable, but will still appear in the _source field of returned hits. These fields will not be added to the mapping, and new fields must be added explicitly into the content type.
+
+You can reactivate the dynamic mapping with this environment variable:  `EMSCO_DEFAULT_BULK_SIZE='true'`. But it's not recommended. Check the [EMSCO_DEFAULT_BULK_SIZE documentation](elasticms-admin/environment-variables.md#emscodynamicmapping)
+
 ## version 5.7.x
 
 * Added twig function [ems_template_exists](./site-building/twig.md#ems_template_exists)