When activating 3G service on an iOS device using a custom Access Point Name (APN), the error message "Could not activate cellular data network: PDP authentication failure" may appear.

This document describes the security content of iOS 5.1.1 Software Update, which can be downloaded and installed using iTunes. For the protection of our customers, Apple does not disclose, discuss, or confirm security issues until a full investigation has occurred and any necessary patches or releases are available. To learn more about Apple Product Security, see the Apple Product Security website. For information about the Apple Product Security PGP Key, see "How to use the Apple Product Security PGP Key." Where possible, CVE IDs are used to reference the vulnerabilities for further information. To learn about other Security Updates, see "Apple Security Updates".

Learn how to use AirPlay to stream videos, music, and photos wirelessly from your iPhone, iPad, iPod touch, or iTunes on your computer, to your HDTV and speakers via Apple TV (2nd and 3rd generation), or to your AirPlay speakers or receivers, including AirPort Express. 

Use these steps if: The AirPlay icon doesn't appear on your iOS device, or iTunes on your computer, after following instructions about how to use AirPlay or AirPlay Mirroring. or There are performance issues while using AirPlay streaming or AirPlay Mirroring.

In certain situations, iPhone 4S may have difficulty recognizing a micro-SIM card, resulting in the following behaviors: "Invalid SIM" or "No SIM Card installed" alert appears intermittently. Status bar displays "No Service" or "Searching" in a location with good network coverage.

iOS 5.1 introduces Japanese language support for Siri on iPhone 4S. This article describes how to enable Siri and availability of the feature during the initial rollout.

This document describes the security content of iOS 5.1 Software Update, which can be downloaded and installed using iTunes. For the protection of our customers, Apple does not disclose, discuss, or confirm security issues until a full investigation has occurred and any necessary patches or releases are available. To learn more about Apple Product Security, see the Apple Product Security website. For information about the Apple Product Security PGP Key, see "How to use the Apple Product Security PGP Key." Where possible, CVE IDs are used to reference the vulnerabilities for further information. To learn about other Security Updates, see "Apple Security Updates".

Read recommendations and guidelines for cleaning your Apple computer, iPad, iPhone, iPod, display, or peripheral device. 

You may be unable to set the time zone on your iPhone or iPod touch.

This document describes the security content of iOS 5 Software Update, which can be downloaded and installed using iTunes. For the protection of our customers, Apple does not disclose, discuss, or confirm security issues until a full investigation has occurred and any necessary patches or releases are available. To learn more about Apple Product Security, see the Apple Product Security website. For information about the Apple Product Security PGP Key, see "How to use the Apple Product Security PGP Key." Where possible, CVE IDs are used to reference the vulnerabilities for further information. To learn about other Security Updates, see "Apple Security Updates".