The fourth and final Android O Developer Preview has been released by Google and it's now available for download.
It has final Android O APIs (API level 26) apart from the latest bug fixes and optimizations, stable version of the Android 26.0.0 Support Library. Incremental updates to the SDK, tools, and Android Emulator system images is expected to be available in next few days.
Again, Google has introduced a new version of Android Testing Support Library that includes new features like Android Test Orchestrator, Multiprocess Espresso, and much more. There are no UI changes found in this release.
The fourth and final Android O Developer Preview is available for the Pixel, Pixel XL, Pixel C, Nexus 5X, Nexus 6P, Nexus Player, and the Android Emulator. It is seen that Pixel XL test device has a super-slow camera, frequent crashes, and lots of Bluetooth issues running the third preview.
The Android O APIs have been stable since release 3, and this leads to the speculation that a stable release of version 26 of the Android Support Library is found. The Android O is expected to have features such as notification of channels, dots, shortcut, pinning, picture-in-picture, autofill background execution limits and other important changes in vital system behavior for O apps.
It also includes adaptive icons, downloadable fonts, and auto-sizing TextView to simplify app development and minimize APK size. Library 26 brings new physics-based animations, downloadable fonts and emojis, and an auto-sizing TextView. Stable Android O update is expected to be released sometime in Q3 2017.
One can visit android.com/beta to get Developer Preview 4 and devices that are enrolled would automatically update when the official version of Android O is released. Google, however, stated "later this summer", while referring to the official Android 8.0 "O" release.
As stated above, the preview is believed to fix some bugs and create a difference in its usage. We as the audience will have to wait for more information from Google about this exciting technology's release.