I'm using Xcode 7.3.1, which supports up to iOS 9.3.1.
Now I'd like to check my app on a device on a relatively current version of iOS (10.x), so I added some OS Support folders (using Xcode 7.3.1 with iOS 10 support ), which seems to have worked well.
Now I need the latest OS support folder (i.e. 10.2.1(14D7)). I have checked other StackOverflow answers, but I haven't found one that helps.