3.0 - add JSON1 SQLite compatibility requirements (#8433)

README.md

@@ -84,7 +84,7 @@ Wagtail supports:
 
 -   Django 3.2.x and 4.0.x
 -   Python 3.7, 3.8, 3.9 and 3.10
--   PostgreSQL, MySQL and SQLite as database backends
+-   PostgreSQL, MySQL and SQLite (with JSON1) as database backends
 
 [Previous versions of Wagtail](https://docs.wagtail.org/en/stable/releases/upgrading.html#compatible-django-python-versions) additionally supported Python 2.7 and earlier Django versions.
 

docs/releases/3.0.md

@@ -160,6 +160,11 @@ References to `BASE_URL` in your settings should be updated to [`WAGTAILADMIN_BA
 
 All uses of `StreamField` should be updated to include the argument `use_json_field=True`. After adding this, make sure to generate and run migrations. This converts the field to use `JSONField` as its internal type instead of `TextField`, which will allow you to use `JSONField` lookups and transforms on the field. This change is necessary to ensure that the database migration is applied; a future release will drop support for `TextField`-based StreamFields.
 
+### SQLite now requires the `JSON1` extension enabled
+
+Due to [`JSONField`](https://docs.djangoproject.com/en/stable/ref/models/fields/#django.db.models.JSONField) requirements, SQLite will only be supported with the JSON1 extension enabled.
+See [Enabling JSON1 extension on SQLite](https://docs.djangoproject.com/en/stable/ref/databases/#sqlite-json1) and [JSON1 extension](https://www.sqlite.org/json1.html) for details.
+
 ## Upgrade considerations - deprecation of old functionality
 
 ### Removed support for Internet Explorer (IE11)