The second OTA (Over the Air) update for the international unlocked HTC One X, weighing in at ~35 MB, is now rolling out in Europe, updating the software to version 1.29.401.7. No changelog has been released yet by HTC, so there is now official word on what changes or fixes the update brings. However, users in the XDA forum are speculating it fixes colour temperature/RGB accuracy, along with a few other minor issues.
You can check whether the update is available on your device by tapping on the Check Now button in Settings » About Phone » Software updates on the phone. Stay tuned for more info on the update as and when it becomes available. If you’ve updated, do let us know if you notice any changes or improvements with the update.