While we have not heard any official word from HTC about the Android 4.3 update to the HTC One, it seems that HTC has started the roll-out in Taiwan according to reports. @LlabTooFeR ( famous and trusted ROM Developer ) has posted an image of the screenshot of the Android 4.3 update for the HTC One on Twitter and this tweet is globally viewed by HTC as well as non HTC users.
The latest Android 4.3 Jelly Bean update for the HTC One is available over-the-air (OTA) and surprisingly the screenshot reveals the software build number to be 3.18.709.2 and is about 512MB in size. The Android 4.3 update on the HTC one fixes certain bugs and brings about improvements such as battery charging animation in power-off state, improvements in gallery and camera with upgrade to colour contrasts in low-light situations and adding soundtracks to highlights. This is all under the roof information and changes as it is not officially yet.