Samsung has planned to upgrade the two-year old Galaxy S4 to latest version of Android OS, Android Lollipop. This proved to be very good news for Galaxy S4 owners as they will get to experience the latest Android OS, on their two-year old devices.
Recently, we have been reported that Samsung has rolled out a Firmware Update for Android 5.0.1 that was initially designed for the Galaxy S4 BLACK-edition GT-I9505, however, with certain tweaks and optimization, some developers over at XDA Forums have been able to be installed on the normal Galaxy S4. This firmware was released in the United Kingdom version of devices.
For further firmware details and instructions for flashing this firmware to your Galaxy S4, you might want to head over to XDA Forums.