Google released the third preview for Android O today, and there are a few goodies inside this developer preview, including the version number for Android O. In previous builds, the about screen would simply say that it was Android O Developer Preview, but it wouldn't include an actual version number. That has changed with this third developer preview. It now shows Android 8.0, which is what many people were expecting for Android O, seeing as Android N was 7.0, Android M was 6.0 and Android L was 5.0.
Android O still has a ways to go before it's finished and available to all. Google isn't slated to release the final version until around August of this year. Which is a similar time frame to what Google used last year with Android N. Launching the stable version ahead of their next hardware release. So it's likely that the Pixel 2 would launch with Android 8.1, similar to the Pixel coming with Android 7.1 last year. Android O is a pretty big update for Android - although still not as huge as Android L or Android Lollipop was a few years ago. With Android O, Google is launching a slew of tiny tweaks to the OS, as well as adding picture-in-picture across the OS. This was a feature that launched in Nougat for Android TV, but now it's coming to smartphones and tablets as well. Google also introduced Notification dots, so you can easily see which apps these are coming from, and also notification levels. So more important notifications are more visible then the less important ones.
Google has one more developer preview that's slated to come out before the final release in Q3. It's likely that it'll launch in early July, setting up for an August launch. With this third developer preview, API's for Android O are now final, so developers can start getting their apps ready for Android O and even start publishing them on Google Play for users to download and use - whether they are on Android O or not. Android O is available for the Pixel, Pixel XL, Pixel C, Nexus 5X, and Nexus 6P in the Android Beta program as of right now.