Android 4.2, Jelly Bean

• Everything in Jelly Bean feels fast, fluid, and smooth. Moving between home screens and switching between apps is effortless, like turning the pages of a book.
• Jelly Bean improves performance throughout the system, including faster orientation changes, quicker switching between recent apps, and smoother and more consistent rendering across the system through vsync and triple buffering.
• Jelly Bean has more reactive and uniform touch responses, and makes your Android device even more responsive by boosting your device’s CPU instantly when you touch the screen, and turns it down when you don’t need it to improve battery life.

Browser and WebView

• Browser has improved performance, CPU and memory efficiency. With better performance for animations and HTML5 canvases and an updated JavaScript Engine (V8), pages load faster and feel smoother.
• Browser now has better HTML5 video support, and has a new user experience. Just touch the video to play and pause, and smoothly transition into and out of fullscreen mode.
• Browser now supports the updated HTML5 Media Capture specification on input elements.
• WebView now supports vertical text, including Ruby Text and other vertical text glyphs.

Internationalization

• New Android 4.2 brings improved font positioning, glyph cache performance, and more accurate placement of accents in Indic, Hebrew, Arabic, Thai and Latin font kerning.
• New New fonts have been added including Roboto Thin and Nanum Gothic for improved Korean font quality.
• Jelly Bean adds support for bidirectional text and more input languages to make the platform accessible to more people around the world.
• There is improved support for Arabic and Hebrew, including a new Arabic font, in the platform.
• You can now enter text in 18 new input languages including Persian, Hindi and Thai. Additional Indic languages Kannada, Telugu, and Malayalam are now supported by the platform.
• Emoji from Unicode 6.0 are now supported.
• If the system language is set to Japanese, Japanese specific versions of glyphs are now properly rendered.

Messaging and Talk

• New Support for group messaging via MMS.
• New notifications display the full text of incoming SMS messages and when you receive an MMS you can view the full photo in the notification.
• When entering recipients for an SMS or MMS a new UI collects recipients as chips, making it easier to compose messages.
• Talk features a new notification style.

Notifications

• You can now take action on notifications directly from the notifications shade.
• Notifications from the same application are grouped together, and the first item is automatically expanded. You can also pinch notifications to expand or collapse them.
• You now get an image preview in notifications after taking a screenshot. You can quickly share the screenshot directly from the notification.
• On 7” tablets you can lock automatic display rotation from the notifications shade.
• For Wi-Fi only devices, quickly see the SSID of the access point you're connected to from the notifications shade.
• You can now touch-hold a notification to identify the application that created it and turn off notifications from that application if needed, or uninstall the application.

People

• The People app is more buttery with smoother animations and improved search performance.
• The People app now retrieves high res photos automatically for Google contacts with public Google+ profiles and displays higher res photos (720x720) on certain devices.
• High res photos set on Google accounts will be backed up and synced across devices.
• The People app has a new 7” tablet layout.
• You can now quickly add your favorite contacts to a home screen, directly from the contact's details page.
• The People app helps you organize your contacts and reduces duplicates with an Improved auto-joining algorithm.
• You can now clear the frequently contacted list from the People app’s favorites tab.

Phone

• New Use the phone app in landscape orientation or while in a car dock.
• New With new filtering options you can quickly manage and review your call log.
• New Improved TalkBack support with a single tap dialpad.
• When you miss a call, a new notification lets you return the call or reply by SMS.
• Incoming visual voicemails are displayed in a new notification that lets you play the message with a single touch.
• During a call a new notification lets you hang up with one touch.
• As part of Project Butter, the dial pad is more responsive. Call log scrolling is smoother, and swiping between tabs in Phone is quick and fluid.
• You can clear your frequently contacted list in the favorite tab of Phone.
• You can now add phone numbers from the call log to existing, read-only contacts.

Settings

• New Access Settings by tapping the Quick Settings icon in the notification shade, or swipe down from the top right on tablets or with two fingers on phones to access settings.
• New Now quickly toggle Wi-Fi and Bluetooth with a long press in Quick Settings.
• Accounts are now displayed in the primary Settings view so you can easily see all the accounts you're signed into on your device.
• You can now easily access all Google Privacy Settings in one place by selecting your Google account from Settings.

Widgets

• Jelly Bean makes it easier to personalize your home screen. As you place widgets on the screen, everything else automatically moves to make room.
• When they're too big, widgets resize on their own. If you choose to resize a widget, apps and widgets will now also move out of the way.
• You can now quickly remove apps or widgets from any home screen by picking them up and flinging them to the edge of the screen.
• Launching apps and returning back home are now faster and smoother.

The new Google experience on Android

Google Search

• New Voice Search lets you launch apps, add meetings to your calendar or even find out when your next appointment is.
• With Jelly Bean, a redesigned experience uses the power of the Knowledge Graph to show you search results in a richer way. It's easier to quickly get precise answers to search queries and explore and browse search results.
• Get to Google Search faster: Google Search can be opened directly from the lock screen by swiping up. For devices with software navigation keys, you can now swipe up from the system bar to quickly access Google Search with Google Now. For devices with a hardware search key, you can tap it to launch Google Search.
• If you're using a wired headset, long press the headset's button to activate Voice Search. You can quickly perform a search query by voice and have the result read back to you.
• You can say "Google" to activate Voice Search from within Google Search.
• For many search queries performed through Voice Search, you can now hear a spoken answer.
• Voice Search recognition is now significantly faster so you can search quickly on the fly.
• Voice Search can now recognize queries even when you have a poor network connection.

Google Now

• New Hotel card: Get one-touch navigation to your hotel when you arrive in a new city.
• New Restaurant reservation card: Be reminded to leave for the restaurant based on live traffic information.
• New Event card: Get reminders about events you purchased a ticket for.
• New Package card: See when your online orders ship.
• New Next appointment card: When you have an appointment, Google Now checks traffic so you can know how long it'll take to get there. You even get a notification for when you should leave.
• New Movies card: See showtimes and ratings for what's playing when you're near a theater. Also be notified when a movie you're interested in arrives at theaters.
• New Concerts card: See when your favorite artists have concerts at nearby venues.
• New Stocks card: Get real-time information about stocks you track.
• New Public alerts card: Receive emergency messages such as storm warnings and earthquake alerts.
• New Developing story & breaking news card: See breaking news and other developing stories that match your interests.
• New Nearby attractions card: See what nearby attractions are popular to visit.
• New Nearby photo spots card: Learn of popular photo spots nearby.
• New Time at home card: When you're in a different time zone, Google Now shows you the time at home so you never feel too far away.
• Flight card: Get real-time flight status and traffic information to the airport.
• Weather card: When you start your day, Google Now shows weather for your current location and work.
• Traffic card: Get traffic conditions and alternate routes before you leave home or work.
• Sports card: You can see live scores and upcoming games and also buy game tickets on the fly.
• Transit card: When you’re near a bus stop or a subway station, this card shows you what buses or trains are next.
• Places card: When you’re on the go, Google Now will suggest nearby bars, restaurants, and places of interest.
• Currency card: When you're traveling, quickly check the local conversion rate.
• Translation card: When you're in a foreign country, you can quickly translate words into the local language.

Google Apps

Calendar

• New Calendar can now be displayed as a widget on phone and tablet lock screens.
• New Calendar now auto completes when entering event titles.
• New New Google Feedback integration lets you give Google feedback and improve Calendar.
• Calendar is more buttery. Content fades in, animations are sprinkled throughout, and swiping/paging between days is smoother.
• Calendar will now display event colors if you've assigned your event a color.
• The 'Today' button on the action bar now shows the current day.
• When viewing an event’s details you can now email all the guests with a single tap.
• Notifications for upcoming events now display more of the event description to let you quickly see relevant details without having to open the app.
• Notifications for upcoming events now let you email all the guests without opening the app, and you can choose a quick response such as "Be there in 10 minutes" or type your own.
• A new option in Calendar settings lets you create your own default quick responses for emailing guests.
• You can now snooze an upcoming event reminder right from the notification.
• Calendar has a new 7” tablet layout.
• When viewing Calendar in portrait orientation on tablets, you can hide or expand controls to give you complete control over how you view your Calendar space.
• Calendar will now remember whether you've chosen to hide or expand controls so you have a consistent experience viewing Calendar whenever you open it.

Google+

• New You can share Photo Spheres with your circles or publicly, and anyone you share with can experience them on Google+ on their desktop.
• New Photo Spheres are now also saved in Instant Upload.
• As you swipe through the stream, large bold photos now fall into place with animations giving you a more interactive browsing experience.
• Google+ on tablets features a new magazines layout in the stream.
• You can now create and manage Google+ Events right from your device. Posts and photos are saved to the event so you can relive it at any time.
• Party Mode lets you instantly upload and share photos during an Event so you capture all the right moments in one place.
• New notifications let you +1, comment, or reshare without having to open the Google+ app.
• You can now see live video streams of all participants in a Hangout.
• A new navigation menu lets you easily navigate through the app and quickly see Google+ notifications.
• When viewing a post you can now swipe to expand and view comments.

Chrome

• New Chrome is the standard browser on Nexus 4, Nexus 7 and Nexus 10.
• As a part of Project Butter, Chrome is optimized for fluid and responsive interaction with web content.
• To get you started a new product tour guides you through Chrome’s features.
• Quickly change tabs by dragging your thumb from the edges of the screen.
• Chrome has a new look and feel for the 'Other Devices' page.
• Chrome has simplified application-level settings which are more consistent with the rest of the platform.

Google Play

• A new set of recommendations widgets use a variety of signals — content that people with similar tastes have purchased, stuff that's popular around where you live, content people in your Google+ circles have +1'ed, and more — to recommend new content like apps, games, music, and movies.
• A new My Library widget, which displays all of your recent movies, books, music, and magazines and dynamically changes based on what you've been engaging with recently.
• Smart App Updates ensure that only the parts of an application that have changed will be downloaded when you next update it, saving time, bandwidth, and battery.
• App encryption for paid apps.