Several years experience in java including mobile java and android java app experience and, of course, start-up experience. My Senior Android App Design and Development skills are finely tuned by building my own andriod apps and scoring in the top 10% every month at StackOverflow answwering other developers questions.
With the Android Platform having 83% of the world-wide market and 80% of the US market AND the older android 4.x devices being 50% of that market OS Fragmentation Solutions become a FOCUS ON CONSISTENT VISUAL BRANDING. Sure you want your android app to function but also you want the visual and the feature-set to be as close to the same as possible on both the older android 4.x devices and the new android 7.x devices.
The BAD NEWS is that Google only minimal back-ports new UI features in the form of the Android Suppport Libs they supply and those same libs only have the minimal Google Material Design implemented. My solution is an investment of my development time in creating an integrated additional set of Android Support Libs that fully port not only cool new UI features but also full Google Material Design to Android 4.x devices.
I am one of the few Android App Design-Dev Shops that creates some independent apps separate from client android apps. The current android app I am develpoing is a task applications for some very diverse work-flows that is evident in the enterprise world.