Android 4.3, HTC Sense 5.5 rolling out to HTC One
Google Android 4.3 Jellybean update for the HTC One has started rolling to devices. It also includes an update to HTC Sense 5.5 UI.
Depending on the region source, you should be getting the updates by now. We recently bought a red HTC One which could have come from Hong Kong.
Key features of Android 4.3 are posted here.