Sprint has announced in its official support forums that the Android 4.4 and Sense 5.5 update for its HTC One is now available for manual pull. In order to check for the update, HTC One owners can head into Settings > System updates > HTC software update > Check now. So far it looks like Sprint HTC One owners haven't had much luck in pulling the update, but HTC executive Mohammad Versi has confirmed that Sprint will be the first U.S. carrier to update its One to KitKat. Sprint adds that the update is scheduled to begin pushing out to users on Feb. 11.
Neither HTC nor Sprint have posted an official changelog for this update quite yet, so it's not yet clear what changes this update packs beyond a bump to Android 4.4 and Sense 5.5. The move to KitKat and a newer version of Sense ought to bring with it quite a few goodies, though, and so it's probably worth the effort to check for the update manually sometime in the next day or two if you've got a Sprint HTC One that you call your daily driver. You can also stay tuned to PhoneDog and I'll give you a shout once more details of the update come to light.
UPDATE: The Sprint admin that originally announced the availability of the One's update has shed some more light on the Android 4.4.2 rollout. He said last night that the update had been put on hold, but this morning several Sprint HTC One owners are reporting that the update is now available for download, as evidenced by the screenshot you see below. The same Sprint admin has since put up another post saying that he's received confirmation that the update is "in production" and that HTC One owners should now be able to snag their serving of Android 4.4.2.