Starting next week iPhone owners will not only be able to buy your triple-venti-extra-hot-no-foam latte using Starbucks mobile app, youll be able to tip your barista for making it as well. The king of coffee is updating its app March 19th to add digital tipping for the first time and make the app easier to navigate. If youre not paying attention in line, a new Shake to Pay feature instantly loads your Starbucks card up from anywhere in the app.