Eventually, Android 9 will come to other smartphones, but for now you need either a Pixel or an Essential Phone PH-1, to run Pie. When it does finally arrive on other phones, it likely won't look the same. That's a pity. The new look Pie is a pleasure to use.
Starting at the top, literally, the time display is on the left of the screen while your cell and Wi-Fi connection and battery icons stay on the right. That's so Pie will work well on smartphones with notched screens, such as the Essential PH-1, Huawei P20 Pro, and OnePlus 6.
There's also a new, hidden gesture-based interface. When you install Android 9, you'll see the usual Back, Home, and Overview keys on the display's bottom. But, you can get to Pie's new gesture-based interface and visit Android's future.
You do this by heading to Settings/System/Gestures. Once there, enable "Swipe up on Home button" and say hi to the new gesture interface. Say goodbye to the once ubiquitous Back button and hello to single elongated Home button.
With this, when you do quick swipe up instead of the app drawer, you'll see the Overview page. On it you'll find, like the name says, your most recently opened applications. In addition, you'll find Google search and a bar containing the five apps that Google thinks you're most likely to want to open. If you swipe up again, or just swipe about two thirds of the way up, you'll finally get to the app drawer you know and love.
If you're in an app, you no longer need to go to your homepage to get to the app drawer. Instead, when you swipe from the bottom to the top, you'll go to the app drawer. You can also change apps by swiping up just a bit. This will bring you to the Overview display.
All these changes sound like a bit much. I know they did to me. I found, however, that I picked them up very quickly and they've made using my phone more pleasant than ever.
Speaking of Overview, instead of smaller cards that you roll vertically up and down, it now shows you large cards, which scroll horizontally. This also comes with the aforementioned search bar and contextually selected suggested apps.
So how does Android know which apps to show you? That comes from a change that's hidden under the hood: machine learning. Google pays attention to what you do on your phone and when you do it to give you the applications you're most likely to use.
Machine learning does far more than that though. For example, Android 9's Adaptive Battery learns how you use your apps. So, for example, if you often have Google Maps open, but you seldom use it, Pie will learn to set it to idle so it's no longer sucking down battery juice when you're not using it. Other applications can use Adaptive Battery so over time your Android 9 phone will grow even more efficient at saving your battery life.
Another battery-life saver is Adaptive Brightness. With this, Android adjusts your screen brightness automatically to match your current lighting conditions. This can save a lot of power.
Android 9 also comes with a Dark theme to save even more power. To activate this, go Settings/Display/Advanced. At the bottom of Advanced you'll find Device theme. Click this and choose "Dark" theme for more long-term power savings.
The new notification format won't save you any power, but it will make life easier. For example, quick settings have more colorful and useful notifications. These settings also have their own card now.
This Pie also comes with numerous small improvements. Two of my favorites are its support for up to five simultaneous Bluetooth connections with seamless switching. Now, I've never had five devices at once, but I often have two -- my Plantronics Voyager 5200 headset and my Audi A5 car -- and this has already made my life easier. In no small part, that's because I can set device-specific default volume levels. That's great because while I love to play my music loud, I'd just as soon not have my ear blasted off by a phone call.
Put all these features together, bake at 350 degrees for 15 minutes (no, not really, your phone will fry), and you get the tastiest Android update I've had in years. If you can try it, do. If you can't, well have you thought about getting a new phone with Android 9 support? I would. It's that good.