It's 2019, and I can guarantee that 90%+ of my students use their phones, not even their tablets, for their online courses, and often even to access material for their live courses. It's absolutely imperative that we be given a way to test our courses on the phone Teacher app, in addition to the tablet app. It took me numerous sleepless weeks to create my video presentations, which look absolutely great on my laptop and even my iPad. I didn't realize the text on my gorgeous slides are so tiny as to be illegible on my students' phones. I'd like to find out what else they will have trouble seeing or reading, so I can at least warn them!