Welcoming Android 7.1.1 Nougat

Posted by Dave Burke, VP of Engineering

Android 7.1.1 Nougat!

Today we're rolling out an update to Nougat -- Android 7.1.1 for Pixel and Pixel
XL devices and the full lineup of supported Nexus devices. We're also pushing
the Android 7.1.1 source code to the href="https://source.android.com/">Android Open Source Project (AOSP) so
that device makers can get their hands on the latest version of Android.

With Android 7.1.1 officially on it's way to users, it's a good time to make
sure your apps are ready.

What's in Android 7.1.1?

Android 7.1.1 is an incremental release that builds on the features already
available on Pixel and Pixel XL devices, adding a handful of new features for
consumers as well as optimizations and bug fixes on top of the base Android 7.1
platform (API level 25).

If you haven't explored the developer features, you'll want to take a look at href="https://developer.android.com/guide/topics/ui/shortcuts.html">app shortcuts,
href="https://developer.android.com/about/versions/nougat/android-7.1.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog#circular-icons">round
icon resources, and href="https://developer.android.com/preview/image-keyboard.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">image keyboard
support, among others -- you can see the href="https://developer.android.com/about/versions/nougat/android-7.1.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">full list of
developer features here. For details on API Level 25, check out the href="https://developer.android.com/sdk/api_diff/25/changes.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">API
diffs and the href="https://developer.android.com/reference/packages.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">API
reference.

You can find an overview of all of the href="https://developer.android.com/about/versions/nougat/index.html">Android
Nougat developer resources here, including details on the core Android 7.0
Nougat behavior changes and developer features.c

Coming to consumer devices soon

We're starting the Android 7.1.1 rollout today, and we expect it to reach all
eligible devices over the next several weeks. Pixel and Pixel XL devices will
get the over-the-air (OTA) update, as will Nexus 5X, Nexus 6P, Nexus 6, Nexus 9,
Nexus Player, Pixel C, and General Mobile 4G (Android One) devices. Devices
enrolled in the Android Beta
Program will receive the final version as well. As always, you can also
download and flash this
update manually.

We've also been working with our device manufacturer partners to bring Android 7.1.1
to their devices in the months ahead.

Make sure your apps are ready

Take this opportunity to test your apps for compatibility and optimize them to
look their best on Android 7.1.1, such as by providing href="https://developer.android.com/about/versions/nougat/android-7.1.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog#circular-icons">round
icons and adding href="https://developer.android.com/guide/topics/ui/shortcuts.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">app shortcuts.
We recommend compiling your app with, and ideally targeting, API 25. See our href="http://android-developers.blogspot.com/2016/11/final-update-to-android-7-1-developer-preview.html">recent
post for details.

With the final platform we�re updating the platform and build tools in Android Studio, as well as the
API Level 25 emulator system images. The latest
version of the support library (href="https://developer.android.com/topic/libraries/support-library/revisions.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">25.0.1)
is also available for you to href="https://developer.android.com/reference/android/support/v13/view/inputmethod/InputConnectionCompat.OnCommitContentListener.html">add
image keyboard support, href="https://developer.android.com/reference/android/support/design/widget/BottomNavigationView.html?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">bottom
navigation, and other features for devices running API Level 25 or earlier.

We're also providing downloadable factory and OTA images on the href="https://developers.google.com/android/images?utm_campaign=android_launch_androidnougat_120516&utm_source=anddev&utm_medium=blog">Nexus Images page to
help you do final testing on your Pixel and Nexus devices. To help scale your
testing, make sure to take advantage of href="http://android-developers.blogspot.com/2016/11/android-dev-preview-in-firebase-test-lab.html">Firebase
Test Lab for Android and run your tests in the cloud at no charge through
the end of December.

After your final testing, publish your apps to your alpha, href="https://developer.android.com/distribute/engage/beta.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">beta,
or production channels in the href="https://play.google.com/apps/publish/">Google Play Developer Console.

What's next?

We'll soon be closing open bugs logged against Developer Preview builds, but
please keep the feedback coming! If you still see an issue that you filed in the
preview tracker, just href="https://source.android.com/source/report-bugs.html">file a new issue
against Android 7.1 in the AOSP issue tracker. You can also continue to give us
feedback or ask questions in the href="https://plus.google.com/communities/105153134372062985968/stream/755bb91d-c101-4e32-9277-1e560c4e26d2">developer community.

As href="http://android-developers.blogspot.com/2016/08/taking-final-wrapper-off-of-nougat.html">mentioned
back in August, we've moved Android Nougat into a regular maintenance cycle
and we're already started work on refinements and bug fixes for the next
incremental update. If you have an eligible device that's currently enrolled in
the Android Beta Program, your
device will automatically receive preview updates of upcoming Android Nougat
releases as soon as they are available. If you don't want to receive those
updates, just visit the Beta
site and unenroll the device.

Thanks for being part of the developer preview. Let us know how this year's
preview met your needs by taking a short
survey. Your feedback helps to shape our future releases.

Pixel Security: Better, Faster, Stronger

Posted by Paul Crowley, Senior Software Engineer and Paul Lawrence, Senior Software Engineer

Encryption protects your data if your phone falls into someone else's hands. The
new Google Pixel and Pixel XL are encrypted by default to offer strong data
protection, while maintaining a great user experience with high I/O performance
and long battery life. In addition to encryption, the Pixel phones debuted
running the Android Nougat release, which has even more href="http://android-developers.blogspot.com/2016/09/security-enhancements-in-nougat.html">security
improvements.

This blog post covers the encryption implementation on Google Pixel devices and
how it improves the user experience, performance, and security of the device.

File-Based Encryption Direct Boot experience

One of the security features introduced in Android Nougat was href="https://source.android.com/security/encryption/file-based.html">file-based
encryption. File-based encryption (FBE) means different files are encrypted
with different keys that can be unlocked independently. FBE also separates data
into device encrypted (DE) data and credential encrypted (CE) data.

href="https://developer.android.com/training/articles/direct-boot.html">Direct
boot uses file-based encryption to allow a seamless user experience when a
device reboots by combining the unlock and decrypt screen. For users, this means
that applications like alarm clocks, accessibility settings, and phone calls are
available immediately after boot.

Enhanced with TrustZone� security

Modern processors provide a means to execute code in a mode that remains secure
even if the kernel is compromised. On ARM�-based processors this mode is known
as TrustZone. Starting in Android Nougat, all disk encryption keys are stored
encrypted with keys held by TrustZone software. This secures encrypted data in
two ways:

• TrustZone enforces the href="https://source.android.com/security/verifiedboot/">Verified Boot
  process. If TrustZone detects that the operating system has been modified, it
  won't decrypt disk encryption keys; this helps to secure device encrypted (DE)
  data.
  
• TrustZone enforces a waiting period between guesses at the user credential,
  which gets longer after a sequence of wrong guesses. With 1624 valid four-point
  patterns and TrustZone's ever-growing waiting period, trying all patterns would
  take more than four years. This improves security for all users, especially
  those who have a shorter and more easily guessed pattern, PIN, or
  password.

Encryption on Pixel phones

Protecting different folders with different keys required a distinct approach
from href="http://source.android.com/security/encryption/full-disk.html">full-disk
encryption (FDE). The natural choice for Linux-based systems is the
industry-standard eCryptFS. However, eCryptFS didn't meet our performance
requirements. Fortunately one of the eCryptFS creators, Michael Halcrow, worked
with the ext4 maintainer, Ted Ts'o, to add encryption natively to ext4, and
Android became the first consumer of this technology. ext4 encryption
performance is similar to full-disk encryption, which is as performant as a
software-only solution can be.

Additionally, Pixel phones have an inline hardware encryption engine, which
gives them the ability to write encrypted data at line speed to the flash
memory. To take advantage of this, we modified ext4 encryption to use this
hardware by adding a key reference to the bio structure, within the ext4 driver
before passing it to the block layer. (The bio structure is the basic container
for block I/O in the Linux kernel.) We then modified the inline encryption block
driver to pass this to the hardware. As with ext4 encryption, keys are managed
by the Linux keyring. To see our implementation, take a look at the href="https://android.googlesource.com/kernel/msm/+/android-msm-marlin-3.18-nougat-dr1/fs/ext4/crypto_key.c">source
code for the Pixel kernel.

While this specific implementation of file-based encryption using ext4 with
inline encryption benefits Pixel users, FBE is available in AOSP and ready to
use, along with the other features mentioned in this post.

Understanding APK packaging in Android Studio 2.2

Posted by Wojtek Kalicinski, Android Developer Advocate

Android Studio 2.2 launched recently with href="http://android-developers.blogspot.com/2016/09/android-studio-2-2.html">many
new and improved features. Some of the changes are easy to miss because they
happened under the hood in the Android Gradle plugin, such as the newly
rewritten integrated APK packaging and signing step.

APK Signature Scheme v2

With the introduction of the new href="https://source.android.com/security/apksigning/v2.html">APK Signature
Scheme v2 in Android 7.0 Nougat, we decided to rewrite how assembling APKs
works in the Android Gradle plugin. You can read all about the low-level
technical details of v2 signatures in the href="https://source.android.com/security/apksigning/v2.html">documentation,
but here's a quick tl;dr summary of the info you need as an Android app
developer:

• The cryptographic signature of the APK that is used to verify its integrity
  is now located immediately before the ZIP Central Directory.
  
• The signature is computed and verified over the binary contents of the whole
  APK file, as opposed to decompressed file contents of each file in the archive
  in v1.
  
• An APK can be signed by both v1 and v2 signatures at the same time, so it
  remains backwards compatible with previous Android releases.

Why introduce this change to how Android verifies APKs? Firstly, for enhanced
security and extensibility of this new signing format, and secondly for
performance - the new signatures take significantly less time to verify on the
device (no need for costly decompression), resulting in faster app installation
times.

The consequence of this new signing scheme, however, is that there are new
constraints on the APK creation process. Since only uncompressed file contents
were verified in v1, that allowed for quite a lot of modifications to be made
after APK signing - files could be moved around or even recompressed. In fact,
the zipalign tool which was part of the build process did exactly
that - it was used to align ZIP entries on correct byte boundaries for improved
runtime performance.

Because v2 signatures verify all bytes in the archive and not individual ZIP
entries, running zipalign is no longer possible after
signing. That's why compression, aligning and signing now happens in a
single, integrated step of the build process.

If you have any custom tasks in your build process that involve tampering with
or post-processing the APK file in any way, please make sure you disable them or
you risk invalidating the v2 signature and thus making your APKs incompatible
with Android 7.0 and above.

Should you choose to do signing and aligning manually (such as from the command
line), we offer a new tool in the Android SDK, called href="https://developer.android.com/studio/command-line/apksigner.html?utm_campaign=android_discussion_api_111016&utm_source=anddev&utm_medium=blog">apksigner,
that provides both v1 and v2 APK signing and verification. Note that you need to
run zipalign before running apksigner
if you are using v2 signatures. Also remember the jarsigner tool
from the JDK is not compatible with Android v2 signatures, so you can't use it
to re-sign your APKs if you want to retain the v2 signature.

In case you want to disable adding v1 or v2 signatures when building with the
Android Gradle plugin, you can add these lines to your href="https://google.github.io/android-gradle-dsl/current/com.android.build.gradle.internal.dsl.SigningConfig.html">signingConfig
section in build.gradle:

class="prettyprint">v1SigningEnabled false
v2SigningEnabled false

Note: both signing schemes are enabled by default in Android Gradle plugin 2.2.

Release builds for smaller APKs

We took this opportunity when rewriting the packager to make some optimizations
to the size of release APKs, resulting in faster downloads, href="http://android-developers.blogspot.co.uk/2016/07/improvements-for-smaller-app-downloads.html">smaller
delta updates on the Play Store, and less wasted space on the device. Here
are some of the changes we made:

• Files in the archive are now sorted to minimize differences between APK
  builds.
  
• All file timestamps and metadata are zeroed out.
  
• Level 6 and level 9 compression is checked for all files in parallel and the
  optimal one is used, i.e. if L9 provides little benefit in terms of size, then
  L6 may be chosen for better performance
  
• Native libraries are stored uncompressed and page aligned in the APK. This
  brings support for the android:extractNativeLibs="false" option
  from Android 6.0 Marshmallow and lets applications use less space on the device
  as well as generate smaller updates on the Play Store
  
• Zopfli compression is not used to better support Play Store update
  algorithms. It is not recommended to recompress your APKs with Zopfli.
  Pre-optimizing individual resources such as PNG files in your projects is still
  fine and recommended.

These changes help make your releases as small as possible so that users can
download and update your app even on a slower connection or on less capable
devices. But what about debug builds?

Debug builds for installation speed

When developing apps you want to keep the iteration cycle fast - change code,
build, and deploy on a connected device or emulator. Since Android Studio 2.0
we've been working to make all the steps as fast as possible. With Instant Run
we're now able to update only the changed code and resources during runtime,
while the new Emulator brings multi-processor support and faster ADB speeds for
quicker APK transfer and installation. Build improvements can cut that time even
further and in Android Studio 2.2 we're introducing incremental packaging and
parallel compression for debug builds. Together with other features like
selectively packaging resources for the target device density and ABI this will
make your development even faster.

A word of caution: the APK files created for Instant Run or by invoking a debug
build are not meant for distribution on the Play Store! They contain additional
instrumentation code for Instant Run and are missing resources for device
configurations other than the one that was connected when you started the build.
Make sure you only distribute release versions of the APK which you can create
using the Android Studio href="https://developer.android.com/studio/publish/app-signing.html?utm_campaign=android_discussion_api_111016&utm_source=anddev&utm_medium=blog#release-mode">Generate
Signed APK command or the assembleRelease Gradle task.

Test on Android 7.1 Developer Preview in Firebase Test Lab

By Ahmed Mounir Gad, Product Manager, Firebase Test Lab

To deliver the best user experience right out of the gate, Firebase Test Lab for Android allows you to test your apps and ensure their compatibility with multiple device configurations, across OS versions, screen orientations, and locales. With a single click, you can run your tests on hundreds of device configurations in Google Cloud and receive your results quickly.

Today, we�re excited to announce the availability of the Android 7.1 Developer Preview on Firebase Test Lab virtual devices. In addition to testing the Android 7.1 Developer Preview on your physical Android Device with the Android Beta program, or on your local Android Emulator, you can use the Firebase Test Lab to scale your app testing to hundreds of Android virtual devices.

You can also use Firebase Test Lab to perform your own testing. If you don�t have any test scripts, Robo test is ideal for doing your basic compatibility testing on the new platform. It crawls your app in an attempt to find crashes. You can also use the Espresso Test Recorder in Android Studio to record your own instrumentation tests without writing any code.

From now until the end of December (12/31/2016), Firebase Test Lab will be offered at no charge on the Firebase Blaze plan for all virtual devices, to help you ensure the compatibility of your app with the Android 7.1 Developer Preview release, as well as with other Android releases.

Prepare your app for API level 25, then go to the Firebase Test Lab console to run your first test.

Happy testing!

Robo tests uncovering a crash on Android 7.1 Developer Preview for the Flood-It! app.

Keeping Android safe: Security enhancements in Nougat

Posted by Xiaowen Xin, Android Security Team




Over the course of the summer, we previewed a variety of security enhancements in
Android 7.0 Nougat: an increased focus on security with our vulnerability
rewards program, a new Direct
Boot mode, re-architected mediaserver and hardened
media stack, apps that are protected from accidental
regressions to cleartext traffic, an update to the way Android handles trusted
certificate authorities, strict enforcement of verified
boot with error correction, and updates
to the Linux kernel to reduce the attack surface and increase memory
protection. Phew!



Now that Nougat has begun to roll out, we wanted to recap these updates in a
single overview and highlight a few new improvements.

Direct Boot and encryption

In previous versions of Android, users with encrypted devices would have to
enter their PIN/pattern/password by default during the boot process to decrypt
their storage area and finish booting. With Android 7.0 Nougat, we�ve updated
the underlying encryption scheme and streamlined the boot process to speed up
rebooting your phone. Now your phone�s main features, like the phone app and
your alarm clock, are ready right away before you even type your PIN, so people
can call you and your alarm clock can wake you up. We call this feature Direct
Boot.




Under the hood, file-based encryption enables this improved user experience.
With this new encryption scheme, the system storage area, as well as each user
profile storage area, are all encrypted separately. Unlike with full-disk
encryption, where all data was encrypted as a single unit, per-profile-based
encryption enables the system to reboot normally into a functional state using
just device keys. Essential apps can opt-in to run in a limited state after
reboot, and when you enter your lock screen credential, these apps then get
access your user data to provide full functionality.




File-based encryption better isolates and protects individual users and profiles
on a device by encrypting data at a finer granularity. Each profile is encrypted
using a unique key that can only be unlocked by your PIN or password, so that
your data can only be decrypted by you.

Encryption support is getting stronger across the Android ecosystem as well.
Starting with Marshmallow, all capable devices were required to support
encryption. Many devices, like Nexus 5X and 6P also use unique keys that are
accessible only with trusted hardware, such as the ARM TrustZone. Now with 7.0
Nougat, all new capable Android devices must also have this kind of hardware
support for key storage and provide brute force protection while verifying your
lock screen credential before these keys can be used. This way, all of your data
can only be decrypted on that exact device and only by you.

The media stack and platform hardening

In Android Nougat, we�ve both hardened and re-architected
mediaserver, one of the main system services that processes untrusted input.
First, by incorporating integer overflow sanitization, part of Clang�s UndefinedBehaviorSanitizer,
we prevent an entire class of vulnerabilities, which comprise the majority of
reported libstagefright bugs. As soon as an integer overflow is detected, we
shut down the process so an attack is stopped. Second, we�ve modularized the
media stack to put different components into individual sandboxes and tightened
the privileges of each sandbox to have the minimum privileges required to
perform its job. With this containment technique, a compromise in many parts of
the stack grants the attacker access to significantly fewer permissions and
significantly reduced exposed kernel attack surface.




In addition to hardening the mediaserver, we�ve added a large list of
protections for the platform, including:

• Verified Boot: Verified Boot is now strictly enforced to
  prevent compromised devices from booting; it supports error
  correction to improve reliability against non-malicious data corruption.
  


• SELinux: Updated SELinux configuration and increased
  Seccomp coverage further locks down the application sandbox and reduces attack
  surface.
  


• Library load order randomization and improved ASLR:
  Increased randomness makes some code-reuse attacks less reliable.
  


• Kernel
  hardening: Added additional memory protection for newer kernels by
  marking
  portions of kernel memory as read-only, restricting
  kernel access to userspace addresses, and further reducing the existing
  attack surface.
  


• APK signature scheme v2: Introduced a whole-file signature scheme that
  improves verification
  speed and strengthens integrity guarantees.

App security improvements

Android Nougat is the safest and easiest version of Android for application
developers to use.

• Apps that want to share data with other apps now must explicitly opt-in by
  offering their files through a Content
  Provider, like FileProvider.
  The application private directory (usually /data/data/) is now set to
  Linux permission 0700 for apps targeting API Level 24+.
  


• To make it easier for apps to control access to their secure network
  traffic, user-installed certificate authorities and those installed through
  Device Admin APIs are no
  longer trusted by default for apps targeting API Level 24+. Additionally,
  all new Android devices must ship with the same
  trusted CA store.
  


• With Network Security Config, developers can more easily configure network security
  policy through a declarative configuration file. This includes blocking
  cleartext traffic, configuring the set of trusted CAs and certificates, and
  setting up a separate debug configuration.

We�ve also continued to refine app permissions and capabilities to protect you
from potentially harmful apps.

• To improve device privacy, we have further restricted and removed access to
  persistent device identifiers such as MAC addresses.
  


• User interface overlays can no longer be displayed on top of permissions
  dialogs. This �clickjacking� technique was used by some apps to attempt to gain
  permissions improperly.
  


• We�ve reduced the power of device admin applications so they can no longer
  change your lockscreen if you have a lockscreen set, and device admin will no
  longer be notified of impending disable via onDisableRequested().
  These were tactics used by some ransomware to gain control of a
  device.

System Updates

Lastly, we've made significant enhancements to the OTA update system to keep
your device up-to-date much more easily with the latest system software and
security patches. We've made the install time for OTAs faster, and the OTA size
smaller for security updates. You no longer have to wait for the optimizing apps
step, which was one of the slowest parts of the update process, because the new
JIT compiler has been optimized
to make installs and updates lightning fast.


The update experience is even faster for new Android devices running Nougat with
updated firmware. Like they do with Chromebooks, updates are applied in the
background while the device continues to run normally. These updates are applied
to a different system partition, and when you reboot, it will seamlessly switch
to that new partition running the new system software version.




We�re constantly working to improve Android security and Android Nougat brings
significant security improvements across all fronts. As always, we appreciate
feedback on our work and welcome suggestions for how we can improve Android.
Contact us at security@android.com.

Android N APIs are now final, get your apps ready for Android N!

Posted by Dave Burke, VP of Engineering

As we put the finishing touches on the href="https://developer.android.com/preview/index.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">next release of
Android, which will begin to roll out to consumers later this summer, we�re
releasing the 4th Developer Preview of Android N, including the Android N final
SDK. And thanks to your continued feedback over the last three releases, all of
the APIs are now final as well. If you�ve already enrolled your device in the
Android Beta Program, (available at href="https://android.com/beta">android.com/beta) you will receive an update
to this Developer Preview shortly.

Get your apps ready for Android N

The final SDK for Android N is now available for download through the SDK
Manager in Android
Studio. It gives you everything you need to develop and test against the
official APIs in the Android N platform. Once you�ve installed the final SDK,
you can update your project�s compileSdkVersion to API 24 to
develop with the Android N APIs and build and test on the new platform, for href="https://developer.android.com/preview/api-overview.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">new features
such as Multi-window support, direct-reply notifications, and others. We also
recommend updating your app�s targetSdkVersion to API 24 to opt-in
and test your app with Android N specific href="https://developer.android.com/preview/behavior-changes.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">behavior
changes. For details on how to setup your app with the final SDK, see href="https://developer.android.com/preview/setup-sdk.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">Set up the
Preview. For details on API level 24 check out the href="https://developer.android.com/sdk/api_diff/24/changes.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">API diffs
and the updated href="https://developer.android.com/reference/packages.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">API reference,
now hosted online.

Along with the Android N final SDK, we�ve also updated the href="https://developer.android.com/topic/libraries/support-library/revisions.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">Android
Support Library to 24.0.0. This allows you to use multi-window and
picture-in-picture callbacks, new notification features, methods for supporting
Direct Boot, and new MediaBrowser APIs in a backward compatible manner.

Publish your apps to alpha, beta or production channels in Google Play

Now that you have a final set of APIs, you can publish updates compiling with,
and optionally targeting, API 24 to Google Play. You can now publish app updates
that use API 24 to your alpha, beta, or even production channels in the Google
Play Developer Console. In this way, you can test your app�s
backward-compatibility and push updates to users whose devices are running
Developer Preview 4.

To make sure that your updated app runs well on Android N, as well as older
versions, a common strategy is to use href="https://developer.android.com/distribute/engage/beta.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog">Google Play�s
beta testing feature to get early feedback from a small group of users --
including developer preview users — and then do a staged rollout as you release
the updated app to all users.

How to Get Developer Preview 4

Developer Preview 4 includes updated system images for all supported Preview
devices as well as for the Android emulator. If you are already enrolled in the
Android Beta program, your devices will
get the Developer Preview 4 update right away, no action is needed on your part.
If you aren�t yet enrolled in Android Beta, the easiest way to get started is by
visiting android.com/beta and opt-in your
eligible Android phone or tablet -- you�ll soon receive this (and later) preview
updates over-the-air. As always, you can also download and href="https://developer.android.com/preview/download.html?utm_campaign=android_launch_npreview_061516&utm_source=anddev&utm_medium=blog#flash">flash this
update manually. The N Developer Preview is available for Nexus 6, Nexus 5X,
Nexus 6P, Nexus 9, and Pixel C devices, as well as General Mobile 4G [Android
One] devices and the Sony Xperia Z3.

Thanks so much for all of your feedback so far. Please continue to share
feedback or requests either in the href="https://code.google.com/p/android/issues/list?can=2&q=label%3ADevPreview-N">N
Developer Preview issue tracker, href="https://plus.google.com/communities/103655397235276743411">N
Preview Developer community, or href="https://plus.google.com/communities/106765800802768335079">Android Beta
community as we work towards the consumer release later this summer. We�re
looking forward to seeing your apps on Android N!