The Windows Phone 8X for AT&T is now receiving the Portico software update. The update was first released to the device back last month and even reached the T-Mobile variant of the HTC 8X. Now the AT&T model has joined in and the update with build number 10211 is being offered to the device OTA (Over-the-Air).The Portico update will bring several improvements to the device including the ability to keep your Wi-Fi connected when the display it locked, reject a phone call with a text message and save SMS drafts.
You can check for the update on your HTC 8X by heading over to Settings > Phone Update > Check for Updates. Once your have installed the update head over to Settings > About and make sure you are running software version 8.0.10211.204.
source – WinSource | WMPowerUser