Samsung Galaxy S2 is one of the best mid ranged smartphones so far. The device was launched couple of years ago with default Android 4.3 Gingerbread operating system. However Samsung provided official Firmware update to Android 4.1 Jellybean for this phone but that was last official update. Since then there have been no firmware update provided by Samsung although we are now in era of Android 4.4 KitKat. So, if you are one of Galaxy S2 user and are bored from the same user interface, you should try out the Custom ROMs.
Here is one very good ROM for Galaxy S2. Linaro CarbonRom is based on latest Android 4.3 JellyBean operating system which not only provide your the interface but also the features of Android 4.3 on your S2 smartphone. After installing this ROM you will be able to run apps and games which are made for only Android 4.3 or above running devices. if you are not aware how to update the ROM on your phone, refer the step by step guide provided here for the same. Feel free to comment below if anything required regarding this ROM.