I've been randomly receiving these. It's a notification with a bunch of Asian characters and a solid white dot status symbol. I assume it's some sort of ad-ware, but none of the Avast, AVG, CM Security, Malwarebytes, McAfee, or Norton turn anything up. It appears to be part of an app, but I'm not sure how I would go about finding which one since these appear intermittently. Simply removing apps and seeing if they go away wouldn't really work.
I've got Android 5.1.
I've got Android 5.1.