Since the update is rolling out in waves, don't jump if it hasn't hit your phone yet. You can also try to pull it out of your phone by going to Settings > Software Update > Check for Updates. Some of the new features include the Daydream screen saver, the Battery Percentage Notification that allows you to have a more precise idea about the battery life left on your phone, the new lock screen that removes the ring, a new notifications bar and quick settings, the updated app tray, Auto Exposure and Auto Focus lock on the camera, an updated camera interface and a new recent apps list.
We also have some good news for those with the HTC One X. HTC says that shortly after the update starts rolling out for the HTC One X+, it will start to be pushed out for the AT&T version of the HTC One X. HTC states the update will take 20 minutes to complete. We would suggest that you be connected to a Wi-Fi network when updating your phone. And your battery must be at least 35% charged for the update to complete. If this is the end of the road for the HTC One X+, the phone is going out with a bang.
source: HTC via AndroidCentral