I tried to update from 9.2.10 to 9.3.0 and on running the database update afterwards I get this error:
Modul system
sort_all_config aktualisieren
Fehlgeschlagen:InvalidArgumentException: The configuration property display.default.display_options.empty.area.content.value doesn't exist. in Drupal\Core\Config\Schema\ArrayElement->get() (Zeile 76 in /public_html/core/lib/Drupal/Core/Config/Schema/ArrayElement.php).
Federal client has an airgapped D8 site and they just found out about D9. We've upgraded MariaDB from 5.x to 10.3.7 recently. update.php initially threw a fit over the theme and all the custom modules, but I've fixed those by adding D9 to their minimum requirement. Now the only thing holding update.php back is the following: