The new iOS 5.1 was launched with the latest Apple iPad last week. The iOS 5.1 is released for all iOS 5 compatible devices, which include all versions of the iPad, the iPhone 3GS and above and third-generation and later models of the iPod Touch.

The new OS, which took a three-and-a-half month's extensive investigation, does not bring revolutionary features with it. Rather, the list of new features of the latest iOS 5.1 largely consists of bug fixes and interface tweaks. However, even the minor tweaks have made a major difference in Apple's OS.

iOS 5.1 is now available and as an ardent Apple lover, you should get the latest update on your iDevice.

While most of the Apple fans are going gaga over the latest firmware, check out below the most significant features for which you should update your existing iOS and try the latest one on your iDevice.

1. Fix Battery Drain Issue - Apple's latest iOS 5.1 firmware promised to address bugs affecting battery life. The previous iOS 5 brought along with it bugs that affected battery life and that was one of the major complaints against iPhone 4S. According to Apple, that problem has been fixed with iOS 5.1.

Earlier, after receiving a series of complaints about the battery drain issues with iOS 5, Apple released its first over-the-air iOS update - iOS 5.0.1 - in November last year.

The update, which was expected to fix the bugs affecting battery life, could not meet the user expectations. Later, Apple too acknowledged the failure of the software update. However, this time users who have already updated to iOS 5.1 said to have experienced significant improvement in the battery life and have given thumbs up to Apple's latest OS.

Check out how a number of users have shared their positive feedback via a thread on reddit.

2. Photo Stream - Hinted at during the early beta versions in December, the latest iOS 5.1 update now allows photos to be deleted directly from the Photo Stream on any iDevice running iOS 5.1.

Earlier, the user had to reset the entire Photo Stream on iCloud.com and then toggle it off and again back on to delete unwanted photos out of the photo stream of the locally-stored photos. But now with the latest update, the user has to go to the Photos app.

Then, tap the Photo Stream tab, select an image, and then tap the trash button. The user can also tap the Sharing button before selecting an image, and then choose multiple photos to delete all selected photos at the same time.

Moreover, Apple has released corresponding updates to enable this feature for the Apple TV, iPhoto and the iCloud Control Panel for Windows but an Aperture update is not yet available.

3. Camera Shortcut and iPad Camera App - The latest iOS 5.1 enables the user to access the phone camera from the lock screen without having to enter passwords. With iOS 5.1, instead of tapping the camera icon, the user needs to slide up on the icon to reveal the camera.

Earlier, the iOS 5 added an effective lock screen camera shortcut that allowed users to quickly shoot a photo without having to unlock the iPhone first but complaints related its visibility often bothered Apple.

With the latest update, the camera shortcut will be present at all times and instead of pressing the camera icon to access the camera, the user can now slide up the lock screen. The latest camera shortcuts will now be for iPhone 4S, iPhone 4, iPhone 3GS and iPod touch (fourth generation).

Apple also made a minor but important interface tweak for its camera app. The camera shutter has moved from the menu bar at the bottom of the viewfinder to the right side of the frame. And to increase the ease of the iPad user, the button also rotates accordingly with the iPad when it is changed from portrait to landscape.

4. Face Detection - The latest camera face detection now highlights all detected faces. So, with the latest iOS 5.1 on iPhone 4S, the camera app now will highlight all faces that it detects when the user is trying to snap an image.

5. iTunes Improvement - Along with the release of the latest iOS 5.1, a great numbers of important and hugely-needed improvements have been integrated into the iTunes Match.

In the latest OS, the reliability and the performance quotient of iTunes has been taken care of and improved enormously. The latest OS combines the Genius Playlists and Genius Mixes. Genius helps you get an access to your entire iTunes library via iCloud, allowing a larger selection when creating Genius Playlists.

With iTunes in the Cloud, the music the user buys from the iTunes Store automatically appears on all iDevices. The iTunes additionally lets the user store the entire collection in iCloud, even music that has been imported from CDs or purchased somewhere other than iTunes.

See how to get started with the iTune Match.

Other significant improvements of iOS 5.1 include - 

- Japanese language support for Siri - Audio for TV shows and movies on iPad optimized to sound louder and clearer - Podcast controls for playback speed and a 30 second rewind for iPad - Updated AT&T network indicator - Fixes an issue that occasionally caused audio to drop for outgoing calls