One of the US Carrier AT&T had rolled out the software update to the iphone 5 and 4s. The update is to provide support for Wireless Emergency Alerts. Wireless Emergency Alerts are part of the FCC’s CMAS program and are mandated by law. Once the phone got the update it will be able to receive the emergency alerts. This is the special update of safety messages that is issued by the government.

 The update notifications names as AMBER (America's Missing: Broadcasting Emergency Response) alerts. This indicates the emergency alerts for man-made or natural disasters or Presidential alerts. Whenever the update is available on your phone you can get the message like “Carrier Settings Update: new settings required for your device have been installed”.  After the installation of update there are two Notifications settings menu available on your iphone.

With the help of these settings the user can disable the AMBER alters and emergency alerts. But the user cannot disable the Presidential alerts. To Turn Off the settings Go to Settings >Notifications>Turn On/Off. The update is mandatory for all the users and the carrier not charge for this update.  

Also the user must have iOS6.1.x to receive the carrier update over-the-air. For others when they next update their software via iTunes, the update will include the current carrier settings.