HTC has finally stated rolling out the Android 4.3 Jelly Bean firmware update for the HTC One users in India. The software update version 3.63.707.4 brings HTC Sense 5.5 update with Android 4.3 for Unlocked HTC One. This is a significant update that brings improvements for video highlights, HTC BlinkFeed, Sense TV, enhanced music, and more. The update is available Over the air (OTA) and is sized 704.42MB, so make sure upgrading over Wi-Fi.
HTC One 3.63.707.4 Official Changelog –
To check for update, head over to Settings > About > Software updates.
To install the update, you first need to download and install a small 614KB update. Then reboot your device and check for the update again, 4.3 OTA update should show up.