Just downloaded the 1.5 version of the Delta app to my Android phone last night. Last night, from the "Hi, mnbp" initial screen, I clicked on "Check in AAA to BBB". The link showed my flight but did not offer an option to check in for the flight. However, when I brought up my itinerary from "View my trips" screen, I was able to check in. Now that I am checked in, I can't test this again to see if I missed something originally.