Sony has been a surprisingly developer-friendly Android phone maker, with its Open Devices program giving anyone the opportunity to build and flash custom versions of the OS firmware on its devices. A few days ago Sony published the relevant binaries for the latest AOSP version of Android 8.0 Oreo for a number of its phones, and now it's added two newer Xperia models.
The XZ1 and XZ1 Compact were launched at the end of August at IFA 2017 in Berlin. They're essentially the same as their predecessors, the XZ and X Compact, on the outside, with updated internals such as the Snapdragon 835. Both phones ship with Oreo, so it's no surprise to see them added to the Open Devices program now that it's also offering the newest flavor of Android.
To get involved with the open source community for the devices, head over to the respective GitHub projects for the XZ1 and XZ1 Compact. Before you get started, you might want to read Sony's Android Oreo build guides. It's worth reiterating this stuff is strictly for developers, who can find other interesting Sony open source projects here.
If you have a Sony device and you're wondering if it's going to be updated to Oreo, take a look at this handy list.