Testing the user interface (UI) testing may be the most difficult part of test automation. When we think from the perspective of users there are not hundreds but there may be thousands of different users' environment but it is clear that simulating and testing UI related cases for all possible users' environment is impossible! However we can cover easily the %80 of them by using statistical data taken from analytics tools as Pareto Analysis says 20% of reasons cause the %80 of all problem. If you are doing some kind of internet business, there are two important factors for user environments which are operating system and browsers for normal internet users. Therefore analytic tools should give us feedback about operating system and versions of operating system; browsers and versions of browsers. To get a general trend we can look at the w3shcool.com statistic but sure it is more convenient to take your own statistic depends on your user profile. In general approach
Not a feature, but the future of an app is under testing.