Android 4.3 is the very latest Android firmware to hit the market. Unfortunately, in typical fashion, that does not mean that every device gets it right away. In fact, for the most part, mobiles won’t be equipped with it for quite some time. A good example of that would be the fact that the HTC One has only been updated with the 4.2.2 Jelly bean officially the other day.
Thanks to the CyanogenMod team you can now install the Android 4.3 unofficially via a custom firmware build known as CM 10.2.
This custom firmware will give you the closest thing to 4.3 without it being official. CyanogenMod 10.2 is also based off of the AOSP.
You can get your hands on the file from the direct link below.
To install it, simply do a standard installation via the SD card. You will need to have a custom recovery installed before you start. TWRP recovery is a good one to try.
This file is made only for the HTC One and no other device. It should be fairly distinctive for you to see what the phone is in your hand without having to look at the model number, but if you still are not sure then the model is always there to help.
To use this, the HTC One will need to be unlocked and not restricted to any certain carrier name. If it is in a carrier, then this is locked and will not work.
Download the CM 10.2 Android 4.3 custom ROM .