Edge message Notifications for certain contacts

[AC Question]

Before the software update from marshmallow to nugget, I would get a blue bar on edge of screen when one of my contacts messaged me while I was using an app or not, and I could swipe to the left and it would open the message app and the currant conversation. And it worked with other contacts too. After the update it's not working any more. I would like to know how to turn it back on or if it's gone for good. Thank you for your time.