Now, developers at XDA Forum have succeeded in bringing Android 4.4.4 KitKat with custom CyanogenMod 11 ROM to Nokia X. The current version of ROM doesn’t support three key features: Wi-Fi, camera and storage. You can make calls though and operate the phone as well. A fix for Wi-Fi is on the way, it seems.
You can read all instructions and download the ROM by following XDA Forum link.