How to make your friends believe that you have the latest Android version installed in your Android mobile

You need a rooted phone, Root Explorer or any Explorer which gets you access to system files.
To root your phone see here.
To download Root Explorer see here.

Open Root explorer.
Open system folder.
You will find a file called build.prop.
Press and hold the file to get a menu.
Select Open in Text Editor.
In the line " ro.build.version.release=" edit the existing version and enter the desired version you want.
For example if the actual line reads
ro.build.version.release=2.3.4

The edited line should be something like this
ro.build.version.release=4.0.1

Now save the file and reboot the phone. Now go to Settings and Select About phone to find your Android Version to be 4.0.1! Happy fooling your friends :)