I am pretty sure in the past that I've had the AC app tell me that I could not get an electronic boarding pass when checking in at some AC outstations. Seems like it has been a while though, nothing in recent memory.

However, as a public service message, the AC app will happily give you an electronic boarding pass to depart DEL but customs is letting you go nowhere without a paper one. Which you'll find out after spending 30 mins in line when you get to the front and get turned away, forcing a retreat to the AC counter for a paper one and a line up all over again. So either the app doesn't block you from an electronic boarding pass any more, or it doesn't do it for DEL when it should.