Google has released Developer Preview 4 for Nexus And Pixel Devices. Android O Developer Preview 4 comes with latest bug fixes and optimizations, stable version of the Android 26.0.0 Support Library. The Latest Update Android O Brings notification channels and dots, shortcut pinning, picture-in-picture, autofill, background execution limits and other important changes in latest update, also has adaptive icons, downloadable fonts, and autosizing TextView to simplify app development and minimize APK size.
You can download Android O developer preview 4 images From Android developer website, you can also get OTA images. Android O Developer Preview 4 Is Now Available for Pixel, Pixel XL, Pixel C, Nexus 5X, Nexus 6P, and Nexus Player. Here Google doesn’t announced the name of Android 8.0, but it will be released soon in Q3 2017.