As announced today, Sprint customers can manually update their HTC One devices to the latest version of Android, called KitKat.
According to Sprint, the update is only available per a "customer initiated request", meaning that you need to go to Settings, scroll all the way to the bottom, and select Sprint software update -> Check for updates.
Aside from upgrading the Android version to 4.4, this update brings the latest version of HTC Sense, now at version 5.5. No other details have been released.
Sprint will push the automatic over-the-air update, or OTA, on February 11th. But c'mon, we're not the waiting types. If the manual update check doesn't work for you, keep trying as these usually are staged out geographically. Go grab the update and tell us what you find in the comments below.