The S in iPhone 4S used to stand for "speed," but it's been a couple of years since that was true. iOS 8 wasn't kind to Apple's oldest supported iPhone, which made it even more of a surprise when the company announced in June that the 4S would be hanging around for another year.

That's mostly good news for people still using the four-year-old phone that Apple sold all the way up through late 2014. It doesn't get all of iOS 9's new stuff and it's not nearly as fast as an iPhone 6 or 6S, but competing Android phones from 2011 are all distant memories at this point. This is the longest Apple has ever supported an iPhone, and iOS 9 manages to run about as well as iOS 8 did on the same hardware.

The bad stuff about iOS 8 hangs around, though. Apple keeps adding features that look great on large-screened phones but just make the 4S' 3.5-inch screen feel more and more cramped. Performance does not return to iOS 7 levels, but instead continues to hover near iOS 8 levels. It's not a bad update, but it feels less like a rejuvenation and more like a stay of execution.

What you're missing, and small screen problems

The iPhone 4S is missing out on several hardware-driven features as well as a couple of things that it's presumably not quick enough to run. This list isn't comprehensive, but it includes some of the biggest features from iOS 9 and older versions.

The new Spotlight screen, predictive Siri, and third-party Spotlight search.

Public transit for Maps.

AirDrop.

TouchID.

Handoff for applications, though iPhone call forwarding to other devices works fine.

Support for OpenGL ES 3.0, the Metal graphics API, 64-bit ARMv8 apps, and TouchID/Apple Pay.

Keep in mind that the iPhone 4S is much slower than any other iPhone Apple currently sells. It uses 2.4GHz-only 802.11n Wi-Fi, lacks LTE, and uses an Apple A5 chip that's an order of magnitude slower than the Apple A9 shipping in the iPhone 6S and 6S Plus. Even 2012's iPhone 5 is more than twice as fast.

Andrew Cunningham

Andrew Cunningham

Andrew Cunningham

Andrew Cunningham

Andrew Cunningham

More distressing is the way everything looks on its small display. Some of these are holdovers from iOS 8—the keyboard typing suggestions that devour a big strip of screen space, a Spotlight screen that can't really display more than one result at once with the keyboard up, and so on. iOS 9 introduces new problems with its bigger, bubblier buttons. They have more whitespace and padding than before—on an iPhone 5- or 6-class screen, they just take up more space. On an iPhone 4S screen, they can actually introduce some extra scrolling where iOS 8 could fit everything on the screen at once.

Performance: iOS 8-ish

Things aren't so bad on the performance side of the fence, where things are about the same as they are on the iPad 2—a tiny bit slower according to our tests, but not so much that you'll notice the difference if you're already using iOS 8. For these tests, we connected both OSes to a test iCloud account and then launched each app once to make sure we had gone through any first-launch steps. We then force quit the apps, and then launched them and quit them three more times. The times below are the average of those three runs. The cold boot is the average of two runs, from the first appearance of the Apple logo to the time the lock screen was ready for input.

Application iOS 8.4.1 iOS 9.0 GM Safari 2.29 seconds 2.35 seconds Camera 2.08 seconds 1.94 seconds Settings 1.17 seconds 1.44 seconds Mail 1.57 seconds 1.62 seconds Messages 1.45 seconds 1.49 seconds Calendar 1.15 seconds 1.28 seconds Cold boot 35.99 seconds 43.93 seconds

Going from iOS 7 to iOS 8 resulted in much more noticeable delays. Unfortunately, if you've been sitting on the sidelines with iOS 7 hoping that iOS 9 would bring salvation, that doesn't seem to be the case.

The general user experience on the 4S is still about the same as before—not hopelessly slow, but filled with small wait times as apps load and become ready for input, wait times you won't run into on an iPhone 6. The iPhone 5's hardware is aging more gracefully by comparison and still feels mostly smooth and zippy with iOS 9.

Luckily Apple hasn't given up on optimizing the iPhone 4S' performance—it improves in Javascript benchmarks the same as all the other iDevices, and it doesn't lose any battery life in the update.







Should you upgrade?

Our recommendation for iPhone 4S users is pretty much the same one we gave to iPad 2 users earlier today: if you're running iOS 8, go ahead and upgrade. The small screen is frustrating, but performance is about the same, and for all the stuff you're missing you're still getting a whole bunch of the new features we highlighted in our iOS 9 review. It's got the better, more legible software keyboard, the upgraded first-party apps, and more.

If you're still running iOS 7, at this point we'd say you should probably upgrade, not because you won't take a small performance hit, but because developers will increasingly abandon that older OS version if they haven't already. Apple's iOS updates roll out quickly, but the downside of that is that there's not a ton of incentive for developers to support older releases forever and ever. It's common for developers to support the current release and the immediately previous release, but starting today that doesn't cover iOS 7 anymore. And though it's not going to make your old device feel new again, iOS 9 is probably Apple's best, most stable x.0 iOS release in years.

Apple might surprise us again next year, but this is probably the end of the line for the iPhone 4S. The iPhone 6S is brand new, and if you want a smaller phone that's still a lot faster, the iPhone 5S is cheaper than it's ever been. iOS 9 on the 4S is still perfectly good for a backup phone or a hand-me-down to a less demanding member of the family, but if you use your smartphone heavily you'd be served well by an upgrade at this point.