There are no major changes in the visual design department, so you're unlikely to be upset by changes to the way iOS 9 looks compared with iOS 8. When iOS 7 launched two years ago, many users were horrified by the radical graphical redesign, which took a while to get used to and still annoys a minority of iPhone and iPad owners. That year we advised people to spend time with borrowed iOS 7 devices if they could, and see if they got used to the look of the OS after a week or two - generally interface changes feel earth-shattering at the time, then before you know it you can't remember how it used to look.
But in this case, as we say, there's no significant visual rethink. iOS 9 looks very much like iOS 8, which in turn looked very much like iOS 7.
Other than that, we don't expect there to be any major worries for those expecting an update.
Should you update to iOS 9? The pros
Of course, the pros are that you're getting a new operating system that comes with loads of new features. You can find out about the new features in iOS 9 in more detail in our iOS 9 review, but below is an outline of what you'll be getting.
New features: An exciting new 'Proactive' Siri-activated personal assistant, rather like Google Now; public-transport directions (and other new features) in an improved Maps app; new and improved Multitasking (which is split screen on iPad Air 2), a new News app, an overhauled Notes app.
Design tweaks: As we said, the design changes aren't earth-shattering, but the designers have smoothed a few things over. They keyboard has been slightly redesigned and improved, for example, and some of the visuals are very slighty different to make them easier on the eye.
Fixes, tweaks and stability stuff: Boring but useful, particularly the battery life enhancements that should mean an hour extra power and a new low power mode to extend battery even further.
Future-proofing your device: This will become important in the future. Generally app developers try to make their stuff work with a wide variety of devices, but there will always be a limit. Check your favourite app on the App Store, and under Information you'll see something like 'Requires iOS 6.0 or later'. In a few years apps will start to say things like 'Requires iOS 9.0 or later'.
Should you update to iOS 9? Conclusion
If your iPad or iPhone is up to it (and really up to it - not just officially rated as iOS 9-compatible), you should probably update. Even if you don't care about the new features, the boring stuff - such as bug fixes and compatibility with new apps - is important.
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