The Schedule backup seems can not work correctly now.
when we click the "Apply Schedule" button, all of the setting we selected and entered would disappear.
And the Backup schedule will indicate: Backups are not scheduled
PS. there's ofen return a Warning:
Warning: array_key_exists() expects parameter 2 to be array, boolean given in wp-content/plugins/wponlinebackup/wponlinebackup.php on line 829. But I don't know what's the reason.