The latest version of Apple's mobile operating system iOS 5 can be installed on the iPhone 3GS, iPhone 4, iPhone 4S, iPad, iPad 2, and the third and fourth generation iPod touch.

 

Highlights include iMessage, Newsstand, iCloud support, Twitter support in various standard apps, over the air updates, Wi-Fi syncing with iTunes. and improved notifications.

iMessage is a new app for exchanging text, photo and video messages with other iOS users across the cellular network or Wi-Fi, using the carrier's (usually relatively expensive) SMS service as a fallback. Newsstand handles newspaper and magazine subscriptions, downloading new issues in the background and displaying the cover of the latest issue.

iCloud has been previously described by iTWire. iOS 5 supports iTunes in the Cloud, Photo Stream, Documents in the Cloud, the automatic download of purchased apps and books, backup, Find My iPhone, and synchronisation of contacts, calendar and mail.

Twitter support includes tweeting from the Camera, Photos, Maps, Safari and YouTube apps, including the current location with any tweet, and the display of Twitter usernames and profile pictures in the Contacts app.

There's more goodness in iOS 5, so please read on.

 

 

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Previously, iOS updates were only available by connecting the device to a Mac or Windows PC and using iTunes. As part of Apple's "PC free" efforts to make iPads and iPhones standalone devices, iOS is now able to download software updates over the air.

 

And when you do want to sync an iOS device with iTunes, it's no longer necessary to do so via USB. iOS 5 supports syncing via Wi-Fi (iTunes 10.5 required), but that only happens automatically if the device is connected to an external power source. This is probably most convenient if you habitually drop the iPhone, iPad or iPod touch into a powered dock, or if you're short of USB ports and therefore charge it from a mains adaptor.

Changes to the Notifications system allow new notifications to appear at the top of the screen, and notifications can be seen from the lock screen. Sliding the notification app icon on the lock screen takes you directly to that app, and swiping from the top in any app displays the Notification Center showing all notifications.

iOS 5 incorporates many other changes and improvements, including camera controls and photo editing,  mail, calendar, AirPlay, and accessibility (including support for mobility-impairment input devices).

On the security front, Apple lists 39 broad issues, with one of those covering 60 specific vulnerabilities. WebKit is by far the most heavily patched area.

The various issues addressed in iOS 5 could allow information disclosure, script injection, password exposure (the AppleID password and username, as well as any Wi-Fi credentials were stored in a file accessible to apps, and the parental restrictions passcode was stored in plaintext), cookie leakage, arbitrary code execution, denial of service, and cross-site scripting. The update also revokes DigiNotar certificates.

iOS 5 is installed via iTunes.