We've first learned about Project Treble right before this year's Google I/O 2017. Treble is the most significant low-level change to the Android platform to date. To simplify heavily, it separates the vendor implementation from the Android framework in an effort to avoid lengthy waits for updates. Project Treble is currently supported by the Google Pixel and the Google Pixel XL running Android 8.0 Oreo. We've also learned from the initial announcement that, going forward, all devices shipping with Android 8.0 (like, for example, the upcoming Samsung Galaxy S9 and the just announced Sony Xperia XZ1 series) will come with Treble support. Google also recently announced that they are working with OEMs to bring Project Treble to some existing flagships.
If you have a flagship device that is expected to be updated to Android 8.0 Oreo, how will you know for sure if it supports Project Treble? Unless the release notes outright tell you, which they likely won't given that it's such a low-level change, you'll have to find out another way. Luckily, there's a really, really simple way to find out if an Android Oreo device supports Treble.
In this tutorial, we'll show you how you can tell if your device supports Project Treble. Obviously, for this, you're going to need official, stock Android 8.0 Oreo, since Treble is not supported on 7.0 and lower. And as a reminder, if you have a Google Pixel, Google Pixel XL, or any device that launches with Android 8.0, then that device will for sure support Treble.
Know if Your Android 8.0+ Device Supports Project Treble (Terminal)
Unlike most adb/terminal tutorials we've done previously, this one does not require root, since we're simply getting a build.prop value. You do need Termux (or any other terminal application) going forward, though.
The image on the right shows you how it should look. Once you're set up inside the app, simply type the following command:
getprop ro.treble.enabled
It will return a boolean value, true if your device supports Treble and false if it doesn't.
Know if Your Android 8.0+ Device Supports Project Treble (ADB)
Firstly, you'll need to set up the Android Debug Bridge on your device in order to get going. Follow this tutorial, as it has everything you need to get going on Windows, Linux, and macOS! Then, you'll need to connect your device, either with USB debugging or WiFi debugging (we recommend the latter, but either one will work just fine). Whatever one you choose, be sure to check if it's connected using "adb devices". The image on the right shows you how it should look.
Then, we'll proceed to start the Android terminal inside ADB. For this, use:
adb shell
Afterwards, use the following command:
getprop ro.treble.enabled
The shell will return a boolean value. If it returns true, then congratulations: your device supports Project Treble!
Explanation
It's actually pretty simple. Project Treble isn't really a value that you can see or configure in Settings, device info or other places, however if your device does support it, a preference in build.prop lets any apps know of that fact. This is probably because the Google Play Store needs to read this flag in order to deliver updates for things like graphic drivers and other vendor-related stuff. This flag is required on all devices supporting Treble. The build.prop file is located in the system partition, but its values are readable without root, making this tutorial possible.
However, this does NOT mean you can enable Treble on your device by simply adding this flag to your build.prop since it will do absolutely nothing. As we said above, it requires OEM implementation since it's pretty much a complete rework of a lower layer of Android, and Google is actually working with OEMs to bring Project Treble to existing devices.
As such, this is not something a custom ROM developer can simply bake into their ROM like a regular feature. And should an OEM refuse working with Google to bring it to their device, they can just roll out a simple Android 8.0 update without Treble. The list of OEMs working on Project Treble support for existing phones hasn't been disclosed either. So, until phones start shipping with Android 8.0 (Project Treble is required for all new devices running Oreo), this will be the only way to actually know if your updated Android 8.0 device supports Treble or not.