@SlackHQ why are channels that I subscribe to, but haven’t starred, hidden on my desktop app (yay) but visible on my phone apps (boo). Is this some technology thing? Don’t people want to be more streamlined on their phones?
At the moment, all your channels are visible on mobile, whereas it will depend on your sidebar settings on desktop (Preferences > Sidebar, if you want to check it out). We'll let the team know that you'd like to see the same thing on mobile. 
