Update: Build KTU84F will hit devices between today and April 21st. Sprint hasn't fixed the typo on its support page, but the forum post has the build right.
What a day for an OTA – specifically, Android 4.4.3 for the Nexus 5. Sprint has updated its support page to indicate KTU84F is dropping today, which we understand to be the rumored 4.4.3 release. There is a Sprint-specific tweak in this update, but the software should also be hitting N5s that aren't connected to the Sprint network at the same time.