tnoguchi on "[Plugin: W3 Total Cache] Upgrade to 0.9.4 PHP Error"

I just upgraded to version 0.9.4 on a sandbox site and received the following PHP error with 'WP_DEBUG', true);

Notice: Cannot find configuration key extensions.settings. in /home/wwwlrgsw/public_html/sandbox/wp-content/plugins/w3-total-cache/lib/W3/UI/Settings/SettingsHandler.php on line 91

https://wordpress.org/plugins/w3-total-cache/