Update Galaxy S3 to Android Ice cream Sandwich

Finally, SAMSUNG Galaxy S2 GT I9100 users has something big from Samsung. They can now update their smartphone to the official Ice Cream Sandwich 4.0 via KIES as well as  over-the-air (OTA). Currently, the phone is running on Gingerbread which seems to be outdated by the arrival of newer phones in the market with latest Android OS. The update download size is obviously bigger size (220.31 MB) so do not attempt to upgrade if the internet connection is too slow. 

Improvements in ICS

• Face Unlock and Android Beam are added.
• Mobile network data usage logger.
• Re-sizeable widgets
• Improved Touchwiz UI

Note:

• Non rooted phones can be updated.
• Back up all data such as contacts and memo, messages using any of the phone backup applications. 
• Make sure that phone battery has more than 70% of charge left to keep turned ON for a couple of hours. 
• make sure that you enabled USB debugging in your phone in "Settings > Applications > Development > USB debugging” if you're going to update using KIES software. 
• Make sure that you've installed the latest Samsung KIES application. 
• To update the phone OTA, go to Settings > About the Phone > Software Update, login using your Samsung account details or register new account. 

• Update via KIES is simple is simple as you should be notified about the firmware update when your device is connected via KIES. It will guide you through the process.