WordPress Version: 5.5
/**
* Execute changes made in WordPress 4.0.0.
*
* @ignore
* @since 4.0.0
*
* @global int $wp_current_db_version The old (current) database version.
*/
function upgrade_400()
{
global $wp_current_db_version;
if ($wp_current_db_version < 29630) {
if (!is_multisite() && false === get_option('WPLANG')) {
if (defined('WPLANG') && '' !== WPLANG && in_array(WPLANG, get_available_languages(), true)) {
update_option('WPLANG', WPLANG);
} else {
update_option('WPLANG', '');
}
}
}
}