The update is pushed OTA (over the air) to unlocked models
Samsung kicked off the rollout of Android 4.4.2 KitKat update for Exynos-based Galaxy S4 (GT-I9500) about a week ago and now the LTE model is getting the same treatment.SamMobile reports that the final KitKat build for Galaxy S4 (GT-I9505) is now available for download in some countries. The update is pushed OTA (over the air) in stages, so even if it's available in your country, it may take a while until it reaches your phone.
It is also worth mentioning that the update is only available for the unlocked version of Samsung Galaxy S4 (GT-I9505), so those who own carrier-branded units will have to wait a bit longer.
Those who have yet to be notified of the update can manually check for it by going to Settings / More / About Device / Software update / Update. No word on whether the update is available via Samsung Kies desktop software as well.