Program Overview

Welcome to the Android O Developer Preview, a program that gives you everything you need to make your apps compatible and build for the next version of Android. It's free, and you can get started right away just by downloading the Preview tools.

Timeline and updates

The O Developer Preview runs from 21 March 2017 until the final Android O public release to AOSP and OEMs, planned for Q3 2017.

At key development milestones, we’ll deliver updates for your development and testing environment. Each includes SDK tools, preview system images, emulators, API reference, and API diffs. The milestones are listed below.

• Preview 1 (initial release, alpha)
• Preview 2 (incremental update, beta)
• Preview 3 (final APIs and official SDK, Play publishing)
• Preview 4 (near-final system images for final testing)
• Final release to AOSP and ecosystem

For developers, the focus during the early part of the preview is on making sure your current app is compatible with the new platform, and providing early feedback. In the later part of the preview — but ongoing throughout and beyond the preview — is your work to adopt features in your app and target the new platform.

Please see the migration guide for easy steps to make your app compatible with the new platform, then target the new platform when you're ready.

The first two preview milestones provide an early test and development environment that help you identify compatibility issues in your current apps and plan migration or feature work needed to target the new platform. This is the priority period in which to give us your feedback on features and APIs and file compatibility issues — for all of these, please use the issue tracker. You can expect some API changes across these updates.

At previews 3 and 4 you’ll have access to the final O APIs and SDK to develop with, as well as near-final system images to test system behaviors and features. Android O will provide a standard API level at this time. You can begin final compatibility testing of your legacy apps and refine any new code that is using the O APIs or features.

Also starting in preview 3, you’ll be able to publish apps to devices running Android O at the official API level, such as consumer devices that have opted into the Android Beta program. You can publish into the Google Play alpha and beta channels first, so you can test your apps with Android Beta consumers before distributing broadly on the store.

As you test and develop on Android O, we strongly recommend keeping your development environment up-to-date as preview updates are released.

We’ll notify you when preview updates are available via the Android Developers Blog, as well as this site and the Android O Developer Community.

What's in the O Developer Preview?

The O Developer Preview includes everything you need to test your existing apps on a variety of screen sizes, network technologies, CPU/GPU chipsets, and hardware architectures.

SDK tools

To access the preview, you must first update to the latest version of Android Studio.

Android Studio allows you to download these components through the SDK Manager:

• O Developer Preview SDK and tools
• O Developer Preview emulator system image (32-bit & 64-bit)
• O Developer Preview emulator system Image for Android TV (32-bit)
• O Developer Preview support libraries

We’ll provide updates to these development tools at each milestone as needed.

For complete SDK setup instructions, see the Android O migration guide.

Hardware system images

The O Developer Preview includes hardware system images that you can use when testing and developing on physical devices.

You can download a system image for these devices from the Downloads page:

• Nexus 5X (GSM/LTE) "bullhead" device system image
• Nexus 6P (GSM/LTE) "angler" device system image
• Nexus Player (Android TV) "fugu" device system image
• Pixel "sailfish" device system image
• Pixel XL "marlin" device system image
• Pixel C "ryu" device system image

We’ll deliver updated system images for these devices at each milestone. You can download and flash the updated system images to your test devices manually, as frequently as you need. This is especially useful for automated testing environments where you might need to reflash your device multiple times.

OTA Updates through Android Beta Program

You can get seamless over-the-air updates for any supported device through the Android Beta Program. No flashing is needed.

Documentation and sample code

These documentation resources are available on the Developer Preview site to help you learn about Android O:

• Migrating to Android O has step-by-step instructions for getting started.
• The Behavior Changes point you to key areas where you'll want to test.
• Documentation of new APIs, including an API Overview and detailed developer guides on key features such as notification channels, autofill, and others.
• Sample code that demonstrates how to support notification channels and new features.
• Release notes for the current version of the O Developer Preview, including change notes.

API Reference and diff report

The full preview API reference is available online. New APIs are watermarked for visibility and show "Android O Developer Preview". Note that you can only use these APIs if you are building with the O Preview SDK.

To get a detailed view of new, modified, and removed APIs in each preview release, start with the full and incremental API diff reports, which then links you to the related API reference documentation.

Support resources

As you test and develop on the O Developer Preview, please use these channels to report issues and give feedback.

• Developer Preview Issue Tracker is your primary feedback channel. You can report bugs, performance issues, and general feedback through the issue tracker. You can also check for known issues and find workaround steps. We’ll keep you updated on your issue as it’s triaged and sent to the Android engineering team for review.
• For details on how to report various kinds of issues, see Reporting Preview Issues.
• The Android O Developer Community is a Google+ community where you can connect with other developers working with Android O. You can share observations or ideas or find answers to questions about Android O.

Targeting, preview APIs, and publishing

The O Developer Preview provides a development-only system and Android library that does not have a standard API level. If you want to target the new platform and build with the new Android O APIs, you target the preview version of Android O by setting your app's targetSdkVersion, minSdkVersion, and gradle compileSdkVersion to to “O”. For details, see how to update your build configuration for Android O.

The Android O Developer Preview delivers preview APIs — the APIs will not be official until the final SDK is released, currently planned for the third quarter of 2017. This means that you can expect API changes over time, especially during initial weeks of the program. We’ll provide a summary of changes to you with each update of the Android O Developer Preview.

Note: Although preview APIs may change, underlying system behaviors are stable and ready for testing against right away.

Google Play prevents publishing of apps targeting the O Developer Preview. When the Android O final SDK is available, you’ll be able to target the official Android O API level and publish your app to Google Play via the alpha, beta, and production release channels. Meanwhile, if you want to distribute an app targeting Android O to testers, you can do so via email or by direct download from your site at any time.

How to get started

To get started with Android O, download a system image and install it on a supported device, then read the migration guide for an outline of steps for both compatibility testing and building for O.

Thank you for your participation in the Android O Developer Preview program!