Apple released the iPhone OS 4 upgrade, or iOS 4, for all iPhone and iPod Touch users who had their devices hooked to iTunes this week.

The update weighs in at 378MB, and you need the latest version of iTunes (9.2) to be able to download iOS 4.

Unfortunately, if you have an original iPhone or iPod Touch, your best bet to run iOS 4 is to buy a new iPhone. iOS 4 works with iPhone 3GS, iPhone 3G, and second- and third-generation iPod Touch devices. Take note, however, that not all of its features are compatible with all devices. For example, multitasking is available only with iPhone 4 and iPhone 3GS.

Here's a closer look at some of the highlights of the latest version of the Apple iPhone OS.

Wallpapers for the home screen

Though it isn't a life-changing feature, the fact that you now can select a wallpaper for your iPhone's lock and home screens is pretty exciting. Installing iOS 4 on an iPhone 3GS takes under 10 minutes, and you are also prompted to do a quick carrier-settings update. The device then restarts, restores all your data (music, photos, contacts, email accounts, and so on), and presents you with your new home screen, which can now feature a background image.

You can choose two different images for your lock and home screens, or use the same one throughout. Note that the Calculator icon has been refreshed as well (though the app itself remains the same).

Multitasking is a joy

For many iPhone owners, multitasking was the biggest missing feature. iOS 4 aims to solve this problem. In iOS 4, tapping the Home button to close an app now only hides the app's activity. To see your open apps, you simply double-tap the Home button - the current screen pushes up to reveal a dock. You can swipe left or right to browse through the open apps. To close an app or task, you tap-hold on an app.

If you are reading email and you want to listen to Pandora in the background, for instance, you tap the Home button once, open Pandora, and then double-tap the Home button and tap on Mail to return where you left off.

The problem right now is that the majority of apps are not multitasking-enabled, but in the coming weeks you can expect developers to update the bulk of these apps to add multitasking support.

NEXT PAGE: Unified Inbox and threaded email

  1. There's more to the OS upgrade than just multitasking
  2. Unified Inbox and threaded email
  3. Organise your apps in folders
  4. Improvements to the messages app
  5.  Digital zoom and geo-location for your camera

Multitasking might be the biggest news in the latest version of the iPhone OS, but it has plenty of other useful features and refinements, too. Here's a hands-on look at our 10 favourites.

Unified Inbox and threaded email

If you have more than one email account set up on your iPhone, the unified inbox in Mail is a big improvement. The All Inboxes tab shows all of your email messages in chronological order, though you can't see from which of your accounts each message belongs to. You can set up multiple Exchange accounts, as well.

Email threading is also supported (the number of messages in a conversation appears alongside the subject), and when you tap a thread, you see the list of email messages within it. Additionally, anyone who receives attached documents will appreciate the new option in iOS 4 that allows you to open attachments in third-party applications.

Getting the right words

Misspelling words while typing on the iPhone's small on-screen keyboard should be less troublesome with iOS 4. The update introduces a system-wide spelling checker that extends both to native apps and to third-party apps (at least the ones we tested). You also get a new cut-and-paste option that lets you replace certain words with the clipped text.

NEXT PAGE: Organise your apps in folders

  1. There's more to the OS upgrade than just multitasking
  2. Unified Inbox and threaded email
  3. Organise your apps in folders
  4. Improvements to the messages app
  5.  Digital zoom and geo-location for your camera

Multitasking might be the biggest news in the latest version of the iPhone OS, but it has plenty of other useful features and refinements, too. Here's a hands-on look at our 10 favourites.

Organise your apps in folders

Have lots and lots of apps? Folders are a great way to de-clutter your iPhone's home screens. To make a folder you just tap on an icon until it starts to jiggle, and then you drop that icon on top of another. The folder is named automatically with the type of applications you are grouping, but you can also rename each folder with any label you'd like (and change it again later, if you wish). Keep in mind, however, that you're limited to 12 applications per folder.

If an app within a folder has a notification to display, a badge shows up in the top-right corner of the folder to alert you. To open a folder, just tap on it; repeat that action to close it.

Make playlists in the iPod app

The old On-The-Go playlist in the iPod app was a legacy feature from the early iPod models, but in iOS 4 you can finally create and personalise playlists to your liking. You can either edit a current playlist by rearranging or adding/removing songs, or easily create a brand-new one from scratch by going into the playlist tab and tapping Add Playlist. From there, you can select songs from your entire library to add to your playlist.

You can also control the iPod app from anywhere in iOS 4 by double-tapping on the Home button and swiping right. Controls for play, next song, and previous song (as well as a shortcut to the iPod app) display on your screen.

NEXT PAGE: Improvements to the messages app

  1. There's more to the OS upgrade than just multitasking
  2. Unified Inbox and threaded email
  3. Organise your apps in folders
  4. Improvements to the messages app
  5. Digital zoom and geo-location for your camera

Multitasking might be the biggest news in the latest version of the iPhone OS, but it has plenty of other useful features and refinements, too. Here's a hands-on look at our 10 favourites.

Improvements to the Messages app

 

The Messages app in iOS 4 has also received a few welcome updates. For example, you can now search through your old text messages by pulling down the main message timeline. And while you're composing a text message, a character count now appears above the Send button. The character-count feature is not enabled by default, though; you have to enable it manually from the Settings/Messages menu.

iBooks on your bookshelf

Access to Apple's digital-books store comes though the iBooks app, which is not bundled with the iOS4 update. To get it, you have go to the App Store and download it free of charge. If you're familiar with the iPad version of the app, you'll feel right at home with the iPhone app, which has the same interface.

You can buy and download books from Apple's iBooks store straight from your iPhone, or add your own PDF files by connecting the iPhone to your computer. If you have an iPad as well, iBooks will keep in sync your notes, your bookmarks, and where you left off for each book.

NEXT PAGE: Digital zoom and geo-location for your camera

  1. There's more to the OS upgrade than just multitasking
  2. Unified Inbox and threaded email
  3. Organise your apps in folders
  4. Improvements to the messages app
  5. Digital zoom and geo-location for your camera

Multitasking might be the biggest news in the latest version of the iPhone OS, but it has plenty of other useful features and refinements, too. Here's a hands-on look at our 10 favourites.

Digital zoom and geo-location for your camera

The Camera app in iOS 4 adds a 5x-digital-zoom slider above the shutter button. The slider is easy to access, but the pictures can get a bit blurry if you zoom in a lot (optical zoom is not available on the iPhone).

When you first open the Camera app in iOS 4, it asks you for permission to acquire geolocation data. You'll see this data in action in the Photos app, in a new feature called Places; your photos appear on a map based on where you took them.

The upgrades aren't limited to your still photos, either. When taking videos, you can now tap to focus on your subject--just as you do when taking photos.

Useful enhancements in native apps

Though the previous slides show the biggest changes in iOS 4, you'll find small enhancements in the native apps, too. For example, in the Safari browser, you can now choose from Google, Yahoo, and Microsoft Bing as your default search provider. The browser also displays word suggestions as you type in the search box.

Apple has bumped up the Notes app with wireless syncing, so now you'll always have your notes in sync. This feature works without cables, and it creates a folder in your inbox for over-the-air syncing.

If you keep birthday information with your contacts, you will be pleased to find that the Calendar app now has a place to store that data alongside your schedule. Lastly, heavy typists will appreciate the added support for most Bluetooth-enabled keyboards.

See also: New-look iPhone 4 adds 100 features

  1. There's more to the OS upgrade than just multitasking
  2. Unified Inbox and threaded email
  3. Organise your apps in folders
  4. Improvements to the messages app
  5. Digital zoom and geo-location for your camera