This release restores the ability to run Wagtail against installations of SQLite that do not include the ``fts5`` extension for full-text search support. On these installations, the fallback search backend (without support for full-text queries) will be used, and the database table for storing indexed content will not be created.
If SQLite is subsequently upgraded to a version with ``fts5`` support, existing databases will still be missing this table, and full-text search will continue to be unavailable until it is created. To correct this, first make a backup copy of the database (since rolling back the migration could potentially reverse other schema changes), then run:
..code-block:: console
./manage.py migrate wagtailsearch 0005
./manage.py migrate
./manage.py update_index
Additionally, since the database search backend now needs to run a query on initialisation to check for the presence of this table, calling ``wagtail.search.backends.get_search_backend`` during application startup may now fail with a "Models aren't loaded yet" error. Code that does this should be updated to only call ``get_search_backend`` at the point when a search query is to be performed.
