With so many different versions of the same device (thanks to Samsung & regional carriers) it becomes difficult for developers to build custom roms for all of them, well Samsung Galaxy S4 i9505 owners need not worry about running CyanogenMod on their phones.
Unofficial CyanogenMod 10.1 builds are now available for the Samsung Galaxy S4 i9505 (which uses Qualcomm’s Snapdragon 600 APQ8064T at 1.9GHz).
What’s working:
Audio
GPS
Compass
Proximity Sensor
Wifi
USB mass storage
HW accelerated gui
HW accelerated video
Camera
USB/Wifi tethering
Bluetooth
Not working:
NFC
Download links and instructions can be found here.