We recently learned that the North American HTC One variant will skip over Android 4.2.2 and be updated directly to Android 4.3.
This makes a lot of sense as, though 4.2 was an important release, it was relatively light on new user-facing features. Android 4.3, on the other hand, focused more on adding great new developer tools, something that HTC likely wanted to add to its arsenal as soon as possible.
An early build of Android 4.3 has leaked to XDA, and one developer, LlabTooFeR, has already released a custom ROM with the build as a base. Build 3.09.401.1 still uses Sense 5.0, but has a number of minor improvements, including Bluetooth LE support, improved animations throughout the OS, the ability to use your own music for video highlights and, unfortunately, a task manager added to the app drawer.
Right now, it’s only available as a custom ROM, but we’re expecting HTC to release the update in North America by the end of September.