It has been reported that Galaxy S4 CyanogenMod first nightly builds have now been released. However, for the time being only for Canadian and T-Mobile variants.
It may be added that CyanogenMod is one of the most widely used custom ROMs for Android devices. Android users install custom ROMs because some want to get rid of software modifications that the manufacturer makes, for example Samsung slaps on the TouchWiz UI and HTC adds Sense.
Steve Kondik, better known as Cyanogen, has confirmed that only Canadian and T-Mobile variants support the new builds right now, though in the future the international i9505 variant will be supported as well. He hasn’t confirmed whether Exynos Octa or the other i9500 variants will get support. Do keep in mind that flashing custom ROMs isn’t an easy task for a novice user. Please do so at your own risk
(via Uber Gizmo )