Reports of Warning: Invalid argument supplied for foreach() /backupwordpress/classes/class-schedule.php on line 531

@pdewouters there's a few reports of this error coming in. Can you look into this?

https://app.intercom.io/a/apps/7f1l4qyq/inbox/all/conversations/631507515 

There's another ticket up with FTP access if you want to debug on someones site.