iOS 8 review

iOS 8 is the latest operating system software for iPhone and iPad users, adding a range of exciting new features for Apple devices. In our iOS 8 review we go through all the new features, design and interface changes in iOS 8, iOS 8's security pros and cons (how secure is iOS 8?), the new possibilities the software opens up for app developers and much, much more. Ultimately we will help you decide whether or not you should upgrade your iPad, iPhone or iPod touch from iOS 7 (or earlier) to iOS 8. (The video above shows the install process).

Plus: which iPads and iPhones can run iOS 8, will iOS 8 slow down your iPhone or iPad (particularly older iPhones and iPads), and the answer to other important iOS 8 questions.

Read next: iOS 8 tips & tricks and read these advanced iOS 8 tips you don’t know yet

And if you're wondering what Apple will come up with next, why not read our article about iOS 9? iOS 9 release date rumours and features wishlist

iOS 8 review

Everything you need to know about the iOS 8 beta versions

iOS 8 review: Which iPads & iPhones can run iOS 8?

We've looked at this in more depth in a separate article - Will my iPad or iPhone be able to run iOS 8? But to sum it up: the iPhone 4s and later, the iPad 2 and later, all the iPad minis and the iPod touch 5G will all be able to run iOS 8. Plus, of course, all the new iOS devices launched in 2014 - the iPhone 6 and iPhone 6 Plus both have iOS 8 preinstalled, as do the iPad Air 2 and iPad mini 3.

Looking ahead to rumoured products, the iPad Pro would be expected to run iOS 8, assuming it comes out before iOS 9 is launched (and assuming it doesn't run Mac OS X instead - which is one of the wilder iPad Pro rumours).

iOS 8 review: Will my iPad or iPhone get slower if I update to iOS 8?

This is the logical follow-up question: if your iPad or iPhone is near the bottom of that list of iOS 8-compatible devices - if it's only just compatible, in other words - does that mean it will struggle to run iOS 8?

The truth is that the older generations of iPhone and iPad in particular may indeed get noticeably slower if you update them from iOS 7 to iOS 8.

When iOS 7 launched, the iPhone 4 was the oldest phone that was rated as compatible for an upgrade, and those of us still running such an elderly device (joke!) thought ourselves lucky to make it. But lucky we were not, because the iPhone 4 struggled to do the most basic tasks in iOS 7 - just opening apps felt desperately slow compared to our previous experience on iOS 6.

And sure enough, we've heard fairly widespread reports from owners of the lowest rank of iPhone rated iOS 8-compatible (the iPhone 4s) that iOS 8 is taxing their devices to the utmost.

Sometime Macworld contributor Orestis Bastounis tweeted that he found iOS 8 on his iPhone 4s so slow that he ended up downgrading back to iOS 7.1 (a process that was reasonably straightforward at the time, incidentally, but is now pretty much impossible - see our guide to downgrading from iOS 8 to iOS 7); and the site naboow.com ran tests on an iPhone 4s in iOS 7.1 and iOS 8 and found that some apps took up to 50 percent longer to load in the newer OS.

Your mileage may vary, as we always say, but my personal recommendation to friends and family on the lowest rung of iOS 8-compatible devices (the iPad 2 as well as the iPhone 4s) would be: consider giving it a miss. You won't get all the features in any case; as naboow points out, many of the features you do get were created with a longer screen in mind and won't look brilliant; and most importantly, you might get a noticeable speed drop.

A last point, however: Apple did address the speed loss on the iPhone 4 by releasing iOS 7.1, which while still slower than iOS 6 was noticeably quicker than iOS 7.0. Things might get better in the future.

iOS 8 review: How to update your iPhone or iPad to iOS 8

If you do decide to upgrade to iOS 8, there are a few steps you should take beforehand, and some common problems (such as not having enough space on the device) you should know about.

We discuss such things in depth in our separate article How to update your iPhone or iPad to iOS 8. That article includes a video guide to installing via iTunes if you're struggling with space issues and don't wish to delete anything from your device.

iOS 8 review: Visual design and interface

iOS 8 review

After a succession of operating systems that looked roughly the same, iOS 7 was a stark departure: brighter, lighter, less skeuomorphic and far more modern than iOS 6. As we expected, Apple hasn't done anything as radical as this for iOS 8.

iOS 8's broad aesthetic cues are as far as we can tell almost exactly the same as iOS 7, with the same clean, minimal icons, and transparency effects in place of iOS 6's skeuomorphic design elements. It retains the bold (but very slightly toned down) colour palette of later iterations of iOS 7, which saw the bright green of iOS 7.0 darkened a touch.

iOS 8's interface is largely the same as iOS 7's too. But there are a few changes. Take the app-switching interface. As well as your open apps, this now shows circular thumbnails of recently 'used' contacts. Tap one of these and iOS 8 offers icons that let you ring, FaceTime or text that person, depending on what contact details you have available.

(A couple of tech experts I respect have an odd aversion to this feature, and one of them points out that you can easily turn it off: go to the Settings app, then Mail, Contacts, Calendars, scroll down to Contacts and tap Show In App Switcher. Slide the toggle left so it changes from green to white.)

iOS 8 beta review: Contacts

However, most of the changes to iOS's interface are designed to cope with new features, which we will look at in a moment.

iOS 8 review: Security

But first, we'll briefly address a question that's likely to be occurring to a lot of iPhone owners following the recent leak of nude photos of celebrities: is iOS really as secure as we thought? And do the new features within iOS 8 make the operating system more or less secure?

First of all, Apple insists that the iCloud-related photo leak wasn't down to a failure of iCloud's security systems - it was rather a "very targeted attack on user names, passwords and security questions". And while a few simple precautions will make your photos safe from attack, it's clearly the case that celebrity photos will be a more appealing target (and will be shared more widely) than those of us humble civilians. So by all means take precautions against hacking (and don't ever the mistake of thinking iOS is completely immune to cyber-attack - no platform is completely secure) but equally, don't let this incident make you think that iOS is leaky.

My colleague Karen Haslam discusses this all in more detail in a couple of useful articles: Is Apple's iOS is really safer than Android? and How to prevent naughty pictures appearing on the web. See also: How to set up two-factor authentication on iPhone.

Changes to iOS 8's security

Talking specifically about iOS 8, however, it's worth mentioning a couple of changes from iOS 7 that could conceivably affect platform security - but probably won't.

In broad terms - and we discuss this far more below - Apple has become much more open to user and third-party customisation. iOS 8 allows third-party apps to talk to each other and exchange information, which means you can install widgets and make other changes to system-wide behaviour. And it's possible to download third-party features, such as keyboards, and use them across iOS 8.

For years Apple fans have defended the company's notoriously tight control over the user experience by saying that Android's greater openness makes it less secure. And it's possible that we will see more instances of iOS malware or hacks once the public version of iOS 8 launches, as black hats attempt to persuade users to download rogue software under the guise of third-party features.

But Apple has made every effort to reassure users that this won't happen. It insists that the cross-app communication will be allowed to happen only via iOS itself, and that user information will be made available from one app to another if it obtains user permission - much as apps must seek your permission to access your photos or location data currently. We should also expect Apple to impose tight vetting on downloadable keyboards, just as it does with apps that wish to be sold via the App Store. (Of course, malware sometimes makes it through this process. But it is far less common on the App Store than on Google Play and other companies app marketplaces.)

Because the public version of iOS 8 hasn't been launched yet, we can't yet definitively say that iOS 8 will be secure. But all the signs suggest that it will be far more secure than the alternatives, regardless of the more welcoming approach Apple has taken to third-party customisation.

Rest assured that the many benefits of Apple's new, more open approach will be discussed further in this article.

Improvements to iCloud security in iOS 8

Conversely, some of the improvements Apple is making to iCloud as part of the iOS 8 update will see security tighten up. Three relevant changes:

Security notifications: In two weeks' time, Apple says, it will start notifying users (via email or a push notification) every time someone tries to restore data from iCloud to a device it doesn't recognise, on top of the current notifications for when an iCloud account password is changed.

Two-factor authentication: Once iOS 8 is launched, Apple will require two-factor authentication for access to iCloud accounts from mobile devices.

Handoff means better document syncing and version control, so you're less likely to suffer file corruption or lose versions of documents you've been working on on other devices.

iOS 8 review: New features for users

iOS 8 has a host of brilliant new features, which we'll look at one by one in the following section. But it's worth remarking before we start on one interesting aspect to Apple's presentation: a lot of emphasis was given to developer-specific, highly techie parts of iOS 8, and the new openness Apple is allowing in the things that app developers can do within iOS 8. So we'll divide this into two parts: innate features that iOS 8 itself can do, and developer features that will allow apps to do new things.

If you'd like to see how we got on in our feature predictions leading up iOS 8's unveiling, take a look at our article 'iOS 8 release date, rumours & concept images'. You can also compare what we actually got with what we wished for, in the next section.

iOS 8's new features: Apple Pay

One feature that we didn't know about until Apple announced the final version of iOS 8 on 9 September was a new mobile payments service called Apple Pay. This has since launched in the US, but won't launch in the UK until next year.

iOS 8 review: Apple Pay

Apple Pay lets you pay for goods in-store or online by touching your iPhone to a sensor and then touching your finger to the Touch ID scanner. Your credit-card details are stored within Passbook (which now, icon fans, has an extra red line along the top of its icon to stand for credit cards) but Apple insists that it won't have access to your account details or indeed the details of your purchases. We look at Apple Pay in far more detail in our Apple Pay FAQs.

Apple Pay requires two hardware components: a Touch ID fingerprint scanner and an NFC antenna. The full features of Apple Pay are therefore restricted to the new iPhones (the iPhone 6 and the iPhone 6 Plus), which have been specifically built to support it.

The most recent iPads (the iPad Air 2 and the iPad mini 3) have Touch ID, and get access to a limited version of Apple Pay: they can make app- and web-based payments, but can't be used to pay in store. Although teardowns of the two devices reveal that they have got NFC, which means that in principle Apple could get allow them to use the full version of Apple Pay at some point in the future. Oh, and Apple says the Apple Watch will also support Apple Pay, although it's not entirely clear just yet how the Apple Watch will get around its lack of a Touch ID scanner. 

iOS 8's new features: Messages

Messages - the most heavily used app in iOS, apparently - gets lots of handy tweaks in iOS 8.

Voice messages: The killer feature in iOS 8 Messages is voice. There's a micriphone icon to the right of the message input box, and if you tap and hold this a circular audio recording palette pops up and iOS starts recording what you're saying. Release it and swipe upwards (or tap the upwards-pointing arrow) and the voice message wings its way to the recipient. Tap X or swipe left to cancel the recording; press play to hear what you recorded..

iOS 8 review: How to send a voice message

When the voice message arrives on the recipient's device, it'll display with a neat waveform icon:

iOS 8 review: Voice messages

The voice messages self-destruct (to save memory) after a certain period of time unless you choose to save them. Brilliantly, you can listen to the message in question by simply lifting the iPhone to your ear - iOS detect the motion and interprets the gesture automatically. You can then reply, again without pressing any on-screen controls; speak your reply, then lower the phone and the message is sent.

Mute conversation: You can easily apply iOS's Do Not Disturb mode to a message thread so that you don't get notifications about new posts (but still get notifications about other incoming messages). We've all been in situations that would benefit from this feature: a group message thread has got out of hand and your device keeps buzzing with notifications of new messages.

Other group message changes: Group messages are organised more conveniently in a couple of other ways.

If things get really out of hand in the above scenario, you can leave the group message thread entirely, at any point. If lots of people in the thread have been posting images or videos, you don't need to worry about keeping track of them all, because Messages organises all the attachments in a Messages thread at the bottom of the thread. Finally, you can share your location with other members of a thread indefinitely or for various limited periods of time.

iOS 8 review: Group messages

Above: You can 'Leave this Conversation' (the red option) if you don't wish to receive further messages, or (more diplomatically) simpy mute further notifications by activating thread-specific Do Not Disturb. The various attachments that people in the thread have sent are gathered at the bottom right, and the new location options are blue.

iOS 8's new features: Mail

The Mail app has been updated with gesture support and a wide range of small but convenient tweaks and new features.

You can use gestures to delete, flag or 'unread' messages, swiping across a message to perform the chosen action: it's a single swipe to mark as unread, flick across and tap to flag, or drag all the way across to delete. We've seen gesture support like this in third-party apps but it's nice to see Apple taking developments on board.

iOS 8 review: Flag, archive or delete mail with a gesture

You can swipe across an email to flag or delete it

At the launch event, Apple's Craig Federighi also showcased the ability of Mail to recognise an invitation in a marketing email as an event, and offer to add it to Calendar.

iOS 8 review: Mail

iOS 8's Mail is able to recognise event in emails and offers to add them to the Calendar

Last of all, a new feature called MailDrop allows emailed attachments to be stored in the cloud rather than sent directly with the message, so that the recipient can read the rest of the message (and download the attachment separately) even if a full server would previously have caused a bounceback.

iOS 8's new features: Interactive notifications

iOS 8 lets you accomplish far more without leaving the app you're in, thanks to more interactive notifications.

Facebook, Messages or Twitter notifications pop down into your screen and can be responded to there and then - you get the option to reply or Like, accept or decline Calendar invitations and so on, all from the lock screen or Notification Centre. Alternatively, notifications can be flicked away.

iOS 8 beta review interactive notifications

Previously, swiping across a notification would take you to the app it represented - which was fairly convenient. Now you can just pull down and a keyboard appears, letting you reply there and then

iOS 8's new features: Continuity

This could be the biggest attention-grabber of all, and affects Mac OS X Yosemite as well. It's a very cool concept.

Continuity is the name Apple is giving to enhanced compatibility between its new desktop and mobile platforms, enabling you to for instance answer iPhone calls on your Mac (a notification will appear even if your iPhone is downstairs charging), or continue a message started on iPad on Mac or vice versa. If you're composing an email on your phone and walk up to your Mac, Mail on the Dock in Mac OS X will prompt you that you're composing a message; you can click it to carry on writing the email on your Mac.

Finally - and much requested - iOS 8's Continuity allows you to AirDrop between your mobile device and the Mac.

iOS 8: Continuity

Thanks to the Continuity feature of iOS 8 (and OS X Yosemite), an incoming call appears on all three devices, just like a FaceTime call

We look at the new Continuity features in more detail in a separate article: Apple announces Continuity for Mac and iOS.

iOS 8's new features: QuickType predictive typing

iOS 8 offers a major step forward on the keyboards front.

We'll return to typing in the developer section (superbly, iOS 8 allows the installation of third-party keyboards), but by default iOS 8 supports QuickType, a form of predictive typing that is far more ambitious than the modest auto-correct-level predictions in previous versions. We're not just talking about completing words you've nearly finished typing - in Messages, Mail and similar contexts, iOS 8 offers entire words that it suspects you may wish to use based on context, in a little palette above the keyboard.

For example, if you type a message to a friend suggesting dinner, predictive typing might add "and a movie". Eerie, no?

iOS 8 beta review QuickType

Our testing suggests that QuickType is a potential timesaver that will improve as both the service and the user learn more about the other. On occasion we found ourselves able to type out an entire sentence with single clicks because QuickType was in a particularly astute mood, but in others it was effectively auto-complete with good PR.

iOS 8 review: QuickType predictive typing

QuickType has recognised the simple two-option question being asked, so automatically suggests responses that make sense. Will it be able to cope with more complex contexts? Time will tell

Furthermore, Apple says iOS 8 will be able to learn the words you typically use and understand the context in which you're typing, such as a business or personal communication - messages it sense are intended for business use would see more formal suggestions.

This sounds amazing, but we didn't notice a particularly nuanced grasp of context - although this may be something else that improves with time. The best we could say is that QuickType appeared to sense differences in tone on a per-app basis: in other words, it tended to offer more casual words in Messages, and was more formal in Mail.

We'd got the impression from the keynote that it would be more subtle than this (detecting lexical tendencies relating to specific people and specific conversations, for instance), but we're not yet convinced it's that clever.

And it seems to have some annoying tendencies, such as getting itself into loops, obsessing over particular concepts (we've lost count of the number of times QuickType has suggested words to do with hairdressing, for some reason) and frequently wasting one of the three suggestion boxes to offer the letters you've already typed with inverted commas around them. Typing the letters "chr" into an email, for example, leads QuickType to suggest, from right to left, Christmas, Chris and "Chr" - wouldn't Christ or christian or, well, anything be better than "Chr", which I've already typed and could simply leave as it is?

On the subject of QuickType irritations, take a look at some slightly more comical errors: If history's great writers used QuickType: 10 famous quotes mangled disastrously by iOS 8's predictive typing.

iOS 8 review: QuickType predictive typing

Context sensitive: Exactly the same sentence is being typed in each message, but because one feels like 'business', QuickType suggests formal adjectives. The more friendly message on the right gets vernacular words like 'epic' instead

In order to safeguard privacy, all the information QuickType acquires about your writing style will stay on the device, Federighi insisted.

Despite those minor issues, this remains a really exciting and ambitious feature. Read more information about QuickType in our article Apple knows you so well it can finish your sentences.

iOS 8's new features: Safari

Here's a small but attractive change to the Safari interface: on iPad, you can get a 'bird's eye view' of all the tabs you've got open. (You activate this with a two-finger 'claw' gesture.) And the sidebar from Mavericks is now present in Safari on iOS.

iOS 8 review: Bird's Eye View in Safari

iOS 8 new features: Safari

iPad Safari's new bird's eye view of open tabs

iOS 8 review: Safari sidebar

Safari's sidebar in iOS 8

Safari users can now use DuckDuckGo - a highly privacy-focused search engine - as the default search. This was one of several subtle shots in the keynote event at Google, whose business model is built around gathering large volumes of user data.

In a further nod to privacy fans, Safari on iOS 8 will enable Private Browsing on a per-tab basis.

The main changes in the way you use Safari, however, are likely to be seen in the developer changes we'll discuss later - the ability for third-party apps to share data with Safari and be added to the sharing pane, for instance. (The examples given were a Pinterest 'pinning' feature and an in-Safari translator by Bing. Neither of these are innate to Safari, but third-party apps will be able to create new optional features that you can import.)

iOS 8's new features: Camera

Apple didn't discuss this on stage, but there are some nice updates for the Camera app.

If you tap the screen to focus on a point in the frame, a slider appears underneath that allows you to adjust the exposure compensation on the fly. The implementation is a bit odd - it seems more effective to swipe across the entire screen, when the intuitive thing would be to move the slider itself - but it's a handy extra feature.

Here are some of the other updates in the Camera app in iOS 8:

Time-lapse video: Probably the most imagination-catching of the Camera updates; it's a surprise this didn't get a mention on stage. iOS 8 introduces a new Time-lapse video mode, whereby the Camera app will take photos at dynamic intervals to create a, well, time-lapse video.

Camera timer: Odd this hasn't been included before, really. iOS 8 will feature a camera timer.

Burst and Panorama modes get more inclusive: In iOS 8, graphics optimisations will give users of older iPhones access to the quicker burst mode previously only available to the iPhone 5s (other phones used to get a slower version of this, which only snapped images once every half-second or so). And the iPad gets access to Panorama photos.

Separate focus and exposure controls: You will soon be able to independently control the focus and exposure of a scene in iOS 8. There are several ways the Camera app could implement this, including tap-to-focus with an exposure slider or two separate tap-to-focus reticles.

For more on the new iOS 8 features that didn't get much discussion last night, see 20+ iOS 8 features Apple didn't talk about.

Read: How to get iOS 8-like apps for Time-lapse now

iOS 8's new features: iCloud Drive

iCloud Drive is a sort of Dropbox-esque cloud storage service with seemingly wide cross-platform, cross-app compatibility (although we'll need to test this all out).

If you're in an app like Sketchbook, for instance, you can bring up the iCloud Drive pane, and access the files there. Any edits you make are saved back to the original location. You'll have access to all of those documents on your Mac and Windows as well. There are implications for the Photos apps too, which we'll come to in a bit.

iOS 8's new features: Health

Health is a new app that brings together a variety of health and fitness-related metrics - collated from fitness bands and various third-party devices - that you can monitor easily in a single interface.

iOS 8 beta review: Health

Some analysts expected new hardware to accompany Apple's health-related software updates, and indeed the new Apple Watch has health-monitoring elements built in. But - handily, since the Apple Watch won't launch until some time in 2015 - these features also work with a range of third-party fitness bands and health accessories.

Related to this, Apple also announced HealthKit, which will enable third parties to build their own compatible software. Given the many differences between the healthcare systems in Britain and the US (not least the corporate spending power it commands in America), it's debatable how much we'll see the examples shown in the announcement event - a healthcare monitoring system from a private firm called Mayo Clinic - replicated over here, but it all looks well designed.

Unfortunately, thanks to a last-minute bug, the HealthKit apps have been delayed, and Health is at present a rather limited offering. "We're working quickly to have the bug fixed in a software update and have HealthKit apps available by the end of the month," said an Apple representative.

For more on HealthKit, see Apple's HealthKit in iOS 8 unites health data, talks to doctors.

iOS 8 review: Health

iOS 8's new features: Family Sharing

Family Sharing is a lovely idea, that sounds like it will be both safe and convenient. You set up as a family (informing iOS of the various members of your family and their devices) and it will automatically configure photo sharing, location tracking and the free sharing of digital media across up to six family members (they need to share a credit card). It looks simple, although of course we'll have to reserve judgement until we've wrestled with the feature ourselves.

iOS 8 review: Family Sharing setup

In a nice response to some controversies with high-spending toddlers lately, Family Sharing includes a parental lock feature for app downloads: when your kids try to buy an app, they have to get permission (and a permission request automatically appears on your device). Federighi didn't specify whether this would apply to in-app purchases, but we would assume so, since that tended to be the cause of the worst spending sprees.

iOS 8 new features: Family Sharing

iOS 8's new features: Photos

Photos is where iCloud Drive comes into its own. Photos shot on any iOS device are automatically saved in the cloud and accessible on all of your other iOS devices.

To cope with the enormous volumes of photos this is likely to create on each of your devices, Apple is talking up the enhanced smart search features in iOS 8 Photos. Search terms are returned as locations, times and album names.

You can edit photos within the app (using auto straightening and cropping, for instance, and smart editing based on 'intelligent image analysis') and the edits are transferred across to other iOS devices, pretty much instantly.

iOS 8 review: Photo editing

All of this worked seamlessly in the demo, needless to say. Will our mileage vary? We're also a little concerned about the free allocation of space provided with iCloud, which may get used up quickly. Whether users will be willing to pay for more storage is debatable - although the pricing schemes announced tonight do seem quite reasonable.

iOS 8's new features: Siri

Another new feature we expected was Shazam, and sure enough, it's integrated into Siri: Siri can recognise songs that are playing nearby, and then lets you buy them from iTunes. But that's not the only upgrade for Siri in iOS 8.

Apparently car-bound Siri users can now fire it up by saying "Hey Siri!" No need to tap the controls. (Presumably this means the device is always listening out for commands? Will this impact battery life?) And there's 'streaming voice recognition', which simply means Siri displays what you're saying (or what it thinks you're saying) while you're saying it. If nothing else, this will be a godsend for those moments where you say a long question and then see Siri had absolutely no idea what you were saying.

iOS 8 beta review Siri

Last of all, there are 22 new languages accepted for Siri voice recognition, and 24 new dictation languages.

For more on Siri, take a look at our complete guide: How to use Siri: 'Hey Siri!' and all the other Siri features

iOS 8's new features: Weather

One last - and relatively minor - change relates to the Weather app. Apple's weather data was formerly proved by Yahoo; now, it's from The Weather Channel. We looked at the two forecasts on iOS 7 and iOS 8 at the same moment, and it was pretty much the same - just the odd degree in a few days' time, and a difference of a minute on that day's sunset.

iOS 8 beta review: Weather

iOS 8 review: New features for developers

This might not seem relevant to the average iPhone or iPad user, but the developer-centric updates in iOS 8 are likely to result in some very interesting new apps and app features. Its new willingness to allow app developers more freedom in modifying the user experience and (with permission) affecting the behaviour of other apps is a totally new direction for Apple.

Apple's iOS 8 press release said: "With more than 4,000 new APIs, iOS 8 allows developers to further customise the user experience with major extensibility features and robust frameworks such as HealthKit and HomeKit.

"iOS 8... creates an extraordinary environment for developers, providing them the ability to create amazing new apps like never before."

A lot of the most intriguing stuff in iOS 8, then, isn't about the features Apple itself is providing, but about the opportunities it's creating for third-party app developers. Widgets, Extensibility, Touch ID API, keyboards, home-automation APIs - we'll only grasp the significance of all this once the developer community has got its claws properly into the new kits.

Here are some of the most appealing new dev features.

iOS 8's new developer features: App Store improvements

First up, Apple announced some changes that will make it easier for developers to sell their wares on its store. App bundles are now allowed: if developers and publishers allow it, you'll be able to bundles of multiple apps with a single click (and presumably a discounted price).

As well as screenshots, devs will be able to post preview videos on the App Store. And the apps should be easier to find: Apple says its new Explore search facility is far better at showing the apps you want. (Spotlight also now suggests purchasable apps that fit your search criteria when you search within iOS itself, which may lead to a few extra sales. For that matter, Spotlight is generally more all-encompassing in its search criteria, turning up Wikipedia entries, nearby places and news articles, Apple says, when you run a search on your iOS device.)

Finally, you'll be able to join beta tests of new apps using Apple's TestFlight beta test service.

Apple reveals the future of apps: App Store improvements, SDK changes, Touch ID API, HomeKit & more

iOS 8's new developer features: Extensibility and widgets

Apps can now 'talk to each other', sharing data and modifying each other's behaviour in small ways, although Apple was keen to stress the security measures designed to safeguard this process - any data transferred will move via iOS's own security.

This means, for example, that Pinterest can share its data with Safari and allow the user to add a Pinterest entry to the Safari sharing pane. Or Safari could gain a Bing translate feature, as seen below. (Interesting for Apple to be pushing Bing, isn't it? One in the eye for Google.) 

iOS 8 review: Widgets

But doesn't that sound a bit like... widgets? Yes! iOS 8 finally gets widgets.

See also: The best iOS 8 widgets & extensions to install on your iPhone or iPad

iOS 8 review: Widgets

Craig Federighi demonstrates a SportsCenter widget that he's added to the Notification Centre

You can download widgets from apps and customise their position on the Notifications screen. The example Craig Federighi gave was a (rather brilliant) eBay widget that lets you observe the progress of your auctions, and make a bid from the Notifications Centre itself. (In general, the Notification Centre has been empowered to make far more actions without resorting to the individual apps' own interfaces.)

iOS 8's new developer features: Third-party keyboards

On a related theme, but worth its own entry because of its significance, iOS 8 is open to system-wide third-party keyboards. This is huge, and tackles one of the biggest complaints we had about iOS in the past - its inflexible and backward-looking keyboard.

iOS 8 review: Third-party keyboards

With this change, you'll be able to download a Swype-style swiping keyboard (an actual Swype keyboard upgrade was shown in the demo - see below) and use it throughout iOS 8. This small, simple feature - Swype lets you type by moving your finger smoothly across the letters you want without leaving the screen - is the single element in Android that we used to be most envious of.

iOS 8 review: Swype keyboard

Between this and QuickType, iOS 8 now has state-of-the-art typing options. Assuming QuickType is as good as it looks, typing will be great out of the box, with a range of system-wide upgrades available for power users.

iOS 8's new developer features: Third-party Touch ID

Touch ID, the fingerprint scanner offered on the iPhone 5s (and presumably on further iOS devices yet to be launched) is now being opened up to third parties too. So instead of being confined to unlocking your device and a few key preinstalled apps, you can use your fingerprint to log into banking apps, make secure payments and so on.

As with most of these new developer tools, it remains to be seen how this will actually affect the user. But we'd be surprised if we don't see extensive use of the Touch ID API in third-party apps, because of its great security and convenience.

iOS 8 review: Touch ID API

Touch ID being used to log into the Mint personal finance app

iOS 8's new developer features: Home automation & HomeKit API

The last of the features we predicted, under the speculative heading of 'iHome'. Instead it's known as the HomeKit API, which will let devs build home-automation apps to work with iOS.

One example given was the ability to say "Get ready for bed!" to Siri, causing the system to check that all doors are locked and lights are dimmed, but the possibilities are endless.

iOS 8 review: HomeKit

iOS 8's new developer features: BitCoin and other virtual currencies

A small one, this, but a change to the App Store guidelines may allow virtual currencies to be transferred and accepted.

The relevant clause in the "Purchasing and Currencies" section reads as follows: "Apps may facilitate transmission of approved virtual currencies provided that they do so in compliance with all state and federal laws for the territories in which the app functions."

See Has Apple opened the door to Bitcoin apps?

iOS 8's new developer features: Metal graphics system

We're really getting into developer tech now, but the nutshell summary of the new Metal graphics system is quite appealing: more efficient rendering of detailed 3D graphics. Obviously we look forward to testing the fruits of Metal thoroughly and seeing for ourselves how effective it is.

Tim Sweeney, the boss of Infinity Blade developer Epic Games, was brought on stage to demonstrate a new Zen Garden game built with the Metal technology. He described the new possibilities as "an order of magnitude increase of detail" - with 10,000 petals at one point being simulated, and 3,500 individually animated butterflies.

iOS 8 review: Metal graphics

You'll soon be able to see for yourselves how impressive this all is, because the Zen Garden demo app will be made available for free on the App Store in due course. But the real test of the technology will come in the quality of commercial gaming apps launched in the next few years.

iOS 8's new developer features: Swift programming language

Last of all (and exciting the developers in the audience very much), Apple announced a new programming language for both iOS and Mac software, called Swift. After reporting Apple's (by this point quite openly technical) announcement that Swift features "closures, generics, namespaces, multiple return types and type inference", our US colleague Dan Moren pointed out that "the biggest cheer at this event, you heard it, came at 'namespaces'."

iOS 8 review: Swift programming language

Swift is something we'll be hearing a lot more about in the future. For now, take a look at our article Apple unveils Swift, a new programming language for iOS, Mac for more details.

iOS 8 review: Will I be able to downgrade from iOS 8 to iOS 7 (or iOS 6)?

If you do so in the next few days, it's relatively straightforward - see How to downgrade from iOS 8 to iOS 7.

Beyond that, the window during which Apple signs older versions of iOS closes, and it will get a lot more difficult. Take a look at our older article 'How to downgrade an iPhone or iPad from iOS 7 to iOS 6' to get an idea of what this will involve.

OUR VERDICT

iOS 8 is hugely impressive: it has a host of small but convenient tweaks (particularly in Messages, Mail and Photos, but throughout the system), and opens up new possibilities for app developers to get creative. Widgets are a big addition, third-party keyboards are a huge addition, and we can't wait to see what games developers do with Metal. Most of these new features will appeal more to the seasoned iOS fan than to the beginner - convincing a tech-baffled parent or friend to upgrade may be a harder sell, since there are fewer straightforwardly impressive new features than in iOS 7. But on the other hand, there are essentially no removed features and very few down sides. Those on older devices may find that it slows things down to an unacceptable point, and it is amazingly demanding of storage space when you're installing the update in the first place - but as far as we are concerned these are the only significant points against iOS 8.

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