Before users can update to iOS 5, they must be running iTunes 10.5, which was publicly released on Tuesday. Once installed, an iOS device can then be updated to version 5.
For many, the install of iOS 5 will represent the last time they tether their iOS device to a computer via USB to back up, sync and update through iTunes. Going forward, the software update will allow users to accomplish all of those tasks wirelessly, without the need to use a cable.
iOS 5 is available for the iPhone 4, iPhone 3GS, iPad 2, first-generation iPad, fourth-generation iPod touch, and third-generation iPod touch. Most of the downloads weigh in at more than 700 megabytes, but future delta updates delivered wirelessly will be much smaller, and will be capable of being installed directly from an iPhone, iPad or iPod touch.
An update is also available for the Apple TV, bringing wireless mirroring functionality over AirPlay.
The release of iOS 5 comes two days ahead of the launch of the iPhone 4S, which will also feature the next-generation operating system. The software update was received positively in AppleInsider's in-depth iOS 5 review.
The golden master built of iOS 5 was released to developers last week, representing the same final code that was made public on Wednesday. That has given developers time to make sure their applications can be updated and ensure compatibility with iOS 5 and its new features.
In all, iOS 5 packs more than 200 new features. The most noteworthy among them is Notification Center, which allows users to easily view and manage notifications in one place without interruption; iMessage, a new messaging service that lets you easily send text messages, photos and videos between iOS devices; and Newsstand, a new way to purchase newspapers and magazine subscriptions.
The full list of iOS 5 features highlighted by Apple are:
Notification Center: All your alerts. All in one place. You get all kinds of notifications on your iOS device: new email, texts, friend requests, and more. With Notification Center, you can keep track of them all in one convenient location. Just swipe down from the top of any screen to enter Notification Center.
Choose which notifications you want to see. Even see a stock ticker and the current weather. New notifications appear briefly at the top of your screen, without interrupting what youre doing. And the Lock screen displays notifications so you can act on them with just a swipe. Notification Center is the best way to stay on top of your lifes breaking news.
iMessage: iPad and iPod touch join the conversation. With iMessage, weve created a new messaging service for all iOS 5 users. You can send unlimited text messages via Wi-Fi or 3G from your iPad, iPhone, or iPod touch to anyone with one of those devices. iMessage is built into the Messages app, so you can send text, photos, videos, locations, and contacts. Keep everyone in the loop with group messaging. Track your messages with delivery receipts and optional read receipts, see when someones typing, and enjoy secure encryption for text messages. Even start a conversation on one of your iOS devices and pick up where you left off on another.
Newsstand: A custom newsstand for all your subscriptions. Read all about it. All in one place. iOS 5 organizes your magazine and newspaper app subscriptions in Newsstand: a folder that lets you access your favorite publications quickly and easily. Theres also a new place on the App Store just for newspaper and magazine subscriptions. And you can get to it straight from Newsstand. New purchases go directly to your Newsstand folder. Then, as new issues become available, Newsstand automatically updates them in the background complete with the latest covers. Its kind of like having the paper delivered to your front door. Only better.
Reminders: A better way to do to-dos. Next time you think to yourself, Dont forget to..., just pull out your iPhone, iPad, or iPod touch and jot it down. Reminders lets you organize your life in to-do lists complete with due dates and locations. Say you need to remember to pick up milk during your next grocery trip. Since Reminders can be location based, youll get an alert as soon as you pull into the supermarket parking lot. Reminders also works with iCal, Outlook, and iCloud, so changes you make update automatically on all your devices and calendars.
Twitter: Integrated right into iOS 5. iOS 5 makes it even easier to tweet from your iPhone, iPad, or iPod touch. Sign in once in Settings, and suddenly you can tweet directly from Safari, Photos, Camera, YouTube, or Maps. Want to mention or @reply to a friend? Contacts applies your friends Twitter usernames and profile pictures. So you can start typing a name and iOS 5 does the rest. You can even add a location to any tweet, no matter which app youre tweeting from.
Camera: Capture the moment at a moments notice. Since your iPhone is always with you, its often the best way to capture those unexpected moments. Thats why youll love the new camera features in iOS 5. You can open the Camera app right from the Lock screen. Use grid lines, pinch-to-zoom gestures, and single-tap focus and exposure locks to compose a picture on the fly. Then press the volume-up button to snap your photo in the nick of time. If you have Photo Stream enabled in iCloud, your photos automatically download to all your other devices.
Photos: Enhanced photo enhancements. Turn your snapshots into frame-worthy photos in just a few taps. Crop, rotate, enhance, and remove red-eye without leaving the Photos app. Even organize your photos in albums right on your device. With iCloud, you can push new photos to all your iOS devices. So if youre taking photos on your iPhone, iCloud automatically sends copies to your iPad, where you can quickly touch them up before showing them off.
Safari: Even better site-seeing. iOS 5 brings even more web-browsing features to iPhone, iPad, and iPod touch. Safari Reader displays web articles sans ads or clutter so you can read without distractions. Reading List lets you save interesting articles to peruse later, while iCloud keeps your list updated across all your devices. On iPad, tabbed browsing helps you keep track of multiple web pages and switch between them with ease. And iOS 5 improves Safari performance on all your iOS devices.
PC Free: Independence for all iOS devices. With iOS 5, you no longer need a computer to own an iPad, iPhone, or iPod touch. Activate and set up your device wirelessly, right out of the box. Download free iOS software updates directly on your device. Do more with your apps like editing your photos or adding new email folders on your device, without the need for a Mac or PC. And back up and restore your device automatically using iCloud.
Mail: Your inbox is about to receive some great new features. Format text using bold, italic, or underlined fonts. Create indents in the text of your message. Drag to rearrange names in address fields. Flag important messages. Even add and delete mailbox folders on the fly. If youre looking for a specific email, you can now search in the body of messages. And with iCloud, you get a free email account that stays up to date on all your devices.
Calendar: Get more perspective on your schedule with year view on iPad and week view on iPhone and iPod touch. Tap to create an event and drag to adjust the time and duration. Add, rename, and delete calendars directly from your device. And view event attachments without leaving the Calendar app. iCloud lets you share calendars with friends and family, and it keeps your events in sync on all your devices.
Game Center: iOS is the worlds most popular gaming platform. With iOS 5, you can get your game face on with even more Game Center features. Post a profile picture. Meet your match with new friend recommendations based on the games you play and the players you already know. Discover new games without leaving Game Center. And size up an opponent on the spot with new overall achievement scores.
Wi-Fi Sync: Wirelessly sync your iOS device to your Mac or PC over a shared Wi-Fi connection. Every time you connect your iOS device to a power source (say, overnight for charging), it automatically syncs and backs up any new content to iTunes. So you always have your movies, TV shows, home videos, and photo albums everywhere you want them.
Multitasking Gestures for iPad: iOS 5 includes a few new moves and shortcuts to help you get around even quicker on your iPad: Using four or five fingers, swipe up to reveal the multitasking bar, pinch to return to the Home screen, and swipe left or right to switch between apps.
AirPlay Mirroring for iPad 2: Wow your audience in the board room, classroom, or living room. AirPlay now supports video mirroring. Which means you can wirelessly and securely stream whatevers on your iPad 2 to your HDTV via Apple TV. Everyone in the room sees exactly whats on your iPad display up there on the big screen even when you rotate iPad from portrait to landscape or zoom in and out on photos.
Accessibility: iOS 5 comes with innovative new features that make it easier for people with mobility, hearing, vision, and cognitive disabilities to get the most from their iOS devices. iOS 5 works with specialized hardware accessories. The LED flash and custom vibration settings let you see and feel when someones calling. And improvements to VoiceOver include custom element labeling. These are just a few of the ways iOS 5 continues making advances in the field of accessibility.
For more on iOS 5, see AppleInsider's extensive coverage of the operating system update in Inside iOS 5, parts of which are included below:
Built-in Twitter integration makes tweeting a snap
LED flash on calls, custom accessibility gestures & vibrations
Calendar improvements help make iPhone, iPad PC-free
iTunes Tone Store will offer more text alert options
Notification Center, banner alerts
Inside Apple's move to open up SMS-style messaging to not-mobile clients
Reminders app offers location-aware to-do lists
Safari Reader, private browsing, tabs on iPad
PC Free setup, keyboard shortcuts