The iOS platform has been evolving since it was released early. The current version of the iOS is iOS 5. However, would you like to change the version to iOS 6 or iOS 10 ? That would be changing the name of the OS only and not the actual System. That would be a very nice way to show off to your friends that you have got some inside source in apple and thus have access to a latest version of the iOS.

To perform this and change your iOS number, you will need

• A Jailbreaked iPhone (or other apple device running iOS)
• iFile Cydia Tweak
• Some time

If you do not yet have a Jailbreaked iPhone, you must get your iPhone Jailbreaked. For more information and questions regarding jailbreak please refer to our Jailbreak Guide.

If you have all the requirements fulfilled, follow these steps to change the version number of your iPhone.

• Open iFile by selecting its icon from the Home Screen
• From iFile, go to the root directory and then,
• Open : /System/Library/CoreServices/
• Under this, find a file named SystemVersion.plist

Please note that there is another file known as systemversion.plist% but you do not need to open that.

• You should then see 4 lines and open the last one called ProductVersion.
• Now enter any version that you would like to see. ( I successfully entered 2012)

You can now roam about boasting to your friends, showing off your new iOS version. Please note that doing all this does not actually fetch you that iOS version, it only changes the name. You can try anything Fancy like alphanumeric strings or long names like 1.92.29.23923 etc.

Let it be known before hand that this tweak does not actually modify the OS. This just changes the name of the OS version and it will show same thing in the settings.app when the version it checked. Thus, do not hope for any change in the functionality etc.

Source