HTC has started rolling out the Android 4.3 update for HTC One smartphone in Taiwan today. The update is now available over-the-air (OTA). Your smartphone will automatically notify you of the update once it is ready for your device or you can manually check for the update by going to Settings << About phone << Software update << Update.
As per the update notification, it brings Android 4.3, battery charging animation in power off state, improvements to colour contract in images taken in low-light conditions taken by HTC One camera and ability to add soundtracks in video highlights.
In related news, Jason Mackenzie, President of HTC America, took to Twitter to reveal that HTC One dev edition will also start getting the Android 4.3 update this week, followed by release for regular HTC One in Canada in September-end.
There is no word on update roll-out for other countries right now.