What about iOS 11? Although iOS 11 has received good reviews from beta testers, if you rely on an app that isn’t compatible, you may want to delay your upgrade. Check the App Store listing for each of your key apps, and if they’ve been updated recently, you’re probably OK to upgrade. If you use an iPad, install iOS 11 only once you’re ready for a major interface change, what with the new Dock, the redesigned Control Center, the new Files app, and improved multitasking and drag-and-drop. It’s all good, but it’s noticeably different. Apart from that, we see no significant reason to hold off on iOS 11—you’ll likely appreciate most of its new features.
The question of when to upgrade gets easier with watchOS 4. Although it has some nice new features, like a Siri watch face, improvements to Activity, more workout features, and better integration with Apple Music, it’s not a sea change. With no notable downsides to upgrading, it’s easy for us to recommend upgrading your Apple Watch as soon as you take your iPhone to iOS 11.