Bottom line: Yes, you should upgrade to iOS 9

“Should I upgrade to iOS 9?” is the question I hear the most around launches like this, even more than, “Should I buy a new iPhone?” People generally know if they want the new hardware, but whether or not to put a new OS on a device they already own seems like more of a gamble.I’m here to tell you: iOS 9 is a pretty safe bet.[ Related: 7 tips and tricks for iOS 9 ]First of all, it runs on every device iOS 8 runs on, going all the way back to the iPhone 4s. (And when