5.6.11
broke the site
[06-Dec-2022 08:44:17 UTC] PHP Fatal error: Uncaught TypeError: RWMB_Update_Option::get_api_key(): Return value must be of type string, null returned in /var/web/site/public_html/wp-content/plugins/meta-box/inc/update/option.php:28
Stack trace:
#0 /var/web/site/public_html/wp-content/plugins/meta-box/inc/update/option.php(32): RWMB_Update_Option->get_api_key()
#1 /var/web/site/public_html/wp-content/plugins/meta-box/inc/update/notification.php(101): RWMB_Update_Option->get_license_status()
#2 /var/web/site/public_html/wp-includes/class-wp-hook.php(308): RWMB_Update_Notification->notify('')
#3 /var/web/site/public_html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#4 /var/web/site/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#5 /var/web/site/public_html/wp-admin/admin-header.php(303): do_action('admin_notices')
#6 /var/web/site/public_html/wp-admin/admin.php(239): require_once('/var/web/site/p...')
#7 /var/web/site/public_html/wp-admin/options-general.php(10): require_once('/var/web/site/p...')
#8 {main}
thrown in /var/web/site/public_html/wp-content/plugins/meta-box/inc/update/option.php on line 28