NOKIA BELLE OS:

Nokia has announced the availability of Belle OS upgrade for many of its older phones. Users of Nokia phones including N8, X7, C7, E6, E7, X7 and C6-01 can now officially upgrade to the Belle OS through Nokia Suite.

Earlier called Nokia Symbian Belle, the OS got a new name in late 2011. The company announced that the next version of Nokia's Symbian OS will be called just Nokia Belle.

As Nokia Belle expands its reach, here's looking into all that the OS offer:

6 HOMESCREEN:
With Nokia Belle the number of homescreens expand from the current three to six.
MULTITASKING:
Belle brings improved multitasking functionality. Instead of the old task switcher, Belle lets users flick between live images of their open apps and move quickly between them.
WIDGETS:
Belle brings redesigned widgets like the clock, email, music player, favourite contacts and the calendar which come in five different sizes. The widgets can also be rearranged to create a completely personalised set of screens. 
There are also new 'Toggle' widgets for tasks like switching on Bluetooth and changing settings.
NOTIFICATION:
Just like in the Android and iOS 5, Nokia Belle also comes with a pull down menu for notifications from any homescreen. This menu offers control for missed calls, Wi-Fi, Bluetooth and common settings. 
According to Nokia, the status bar sports a more modern and flat look.
LOCK SCREEN:
Belle also adds changes in the lockscreen. The new update allows users to add colour wallpaper and missed event notifications.
NEW APPS:
The new OS also brings business apps from Microsoft, including Exchange ActiveSync, Sharepoint, OneNote, PowerPoint Broadcaster and Lync\
NFC:
With Belle, Near-Field Communications (NFC) has been deeply integrated into the operating system. Users can share pictures, connect with accessories and check-in with just a tap.