As we reported earlier on Monday, Apple released iOS 4.2.1 for iPhone, iPod touch, and iPad. The patch notes for iPad differ markedly from the patch notes for iPhone (that we already covered) because many features that are new to iPad were introduced in iOS 4.x for iPhone and iPod touch. This includes GameCenter, app multitasking, Folders, and other changes.

Features new to both devices include AirPrint, AirPlay, iTunes TV rentals, a unified mail inbox, alternate fonts for Notes, and free service for Find My iPhone for iPhone 4, iPod touch (4th gen), and iPad.

You can install iOS 4.2 through iTunes. It’s a 551.4MB download.

• Multitasking support for third-party apps
• • Multitasking user interface to quickly move between apps, adjust screen brightness, control playback, lock screen-rotation, and manage print jobs
• • Support for audio apps to play in the background
• • VoIP apps can receive and maintain calls in the background or when device is asleep
• • Apps can monitor location and take action while running the background
• • Alerts and messages can be pushed to apps using push and local notifications
• • Apps can complete tasks in the background
• Folders to better organize and access apps
• Mail improvements
• • Unified inbox to view e-mails from all accounts in one place
• • Fast inbox switching to quickly switch between different e-mail accounts
• • Threaded messages to view multiple e-mails from the same conversation
• • Import .ics files into Calendar
• • Open attachments with compatible third-party apps
• • File or delete search results
• • Option to select size of photo attachments
• • Messages in the Outbox can be edited or deleted
• Game Center
• • Send and receive friend requests
• • Invite friends to multi-player games over the Internet
• • Play multi-player games by auto-matching with other players
• • View leaderboards and Achievements
• • Discover new games from friends
• AirPrint
• • Print mail, photos, Web pages, and more directly to AirPrint compatible printers on a local wireless network
• AirPlay
• • Wirelessly stream videos, music, and photos to Apple TV
• • Wirelessly stream music to AirPlay-enabled speakers or receivers, including AirPort Express
• Find text on Web pages in Safari
• Use Spotlight to search the Web and Wikipedia
• Suggestions and recent searches appear during a Web search
• Support for TV show rentals using iTunes
• Create and edit iTunes playlists on device
• Support for iTunes gifting of apps
• Send and accept calendar invitations wirelessly with supported CalDAV servers
• Support for MobileMe calendar sharing
• Enhanced location privacy
• • A Location Services icon appears in the status bar to indicate when Location Services are being used
• • Location Services can be enabled and disabled per app
• • Indication of apps that have requested your location within the last 24 hours
• Additional Parental Controls
• • Prevent adding friends in Game Center and deletion of apps
• • Restrict changes to Accounts and Location Services settings
• New languages, dictionaries and keyboard
• New fonts available in Notes
• Wirelessly sync notes using IMAP-based mail accounts
• Automatic spellcheck
• Silence background sounds using the Silent switch on the side of iPad
• Improved support for Bluetooth AVRCP
• Persistent WiFi connection to receive push notifications
• Support for Bluetooth braille displays and International braille tables, control VoiceOver using an external keyboard, and other accessibility enhancements
• Wirelesss delivery of carrier settings updates for iPad WiFi + 3G
• • Improved enterprise support
• • Support for third-party Mobile Device Management solutions
• • Enables wireless distribution of enterprise applications
• • Exchange Server 2010 compatibility
• • Support for multiple Exchange ActiveSync accounts
• • Support for Juniper Junos Pulse and Cisco AnyConnect SSL VPN apps (available from the App Store)
• More than 1,500 new developer APIs
• Bug fixes

Products compatible with this software update

• iPad
• iPad WiFi + 3G

We have a separate article posted with the 41 security fixes included in the update.