There are loads of little new features in Android O, with the first developer preview being released today, there's plenty of little things still being found. One of those is the change to the status bar when you pull down the notification shade. In Android Nougat, you simply got the time in the upper-left corner and then a few toggles below it. Now in Android O, you get a whole lot more available to you there.
As you can see in the picture below, you now see the time as well as the date on the left side, along with the Wi-Fi icon, network status, battery percentage and a shortcut to the settings menu, in the status bar. That's a pretty big change compared to what was there on Android 7.0 Nougat. Now this is also a change that most users will likely not even notice, but it is a nice change. However, when you expand the quick toggles, some items are overlapping. Now this is something that Google will likely fix before the final release, so it's nothing to get too upset about, but it's still worth pointing out. You also get an additional toggle in the first row of toggles in the notification shade, which is also pretty handy. These are still customizable, like they were in Android Nougat.
Google announced Android O today, and released the first developer preview. They will be releasing three more developer previews before the final release, which is slated for the third quarter. The Android O developer preview is available for the Nexus 5X, Nexus 6P, Nexus Player, Pixel, Pixel C and Pixel XL. This is likely going to be Android 8.0, but that has not yet been confirmed. The same goes for the name of this new version of Android. It's currently just Android O. Google will likely be making the name official sometime this summer, like they did with Nougat last summer. Many people are betting that it'll be Android Oreo, but that won't happen without Google striking some kind of branding deal with Nabisco, similar to what they did with Nestle for KitKat and Android 4.4 a few years ago.