One of the best feature of slack is the DND . Do not disturb. you can set DND for 30 minutes and when a user send you something he gets a message that you are in DND mode and if something urgent can bypass the DND and send you the message. I think that it is a very good feature for cliq
On Android, I used to get notifications on my phone whether I was in the app, or it was started. Then about a month ago, I stopped seeing notifications on my phone UNLESS I had already started the app. So if I reboot my phone, and never start the app,