The Japanese company, Sony starts rolling out latest Android 8.0 Oreo for Xperia X and Xperia X Compact and this update comes with build number 34.4.A.0.364. The update starts rolling out through OTA (over the air), and your device should be running on build number 34.3.A.0.252 to install the OTA update. Alternatively, experienced users can download the firmware (FTF file) and flash manually.
Android 8.0 Oreo will bring features like Xperia Actions, Autofill, Smart text selection, App shortcut, Reminders, latest Android security patches (January 1, 2018), and more the device. If you own Xperia X (F5121) or Xperia X Compact (F5321) and did not received the OTA notification, you can download and install the update manually.
Before starts, check the new 34.4.A.0.364 software update manually by going to Settings > About phone > Software update. If update found, proceed with installation. We recommend this method, as the manual method is risky.
Note: Back up all important data before manually installing the firmware on your Sony phone.
Note that the full firmware file (FTF file) for Sony devices can be downloaded directly from Sony’s servers using the XperiFirm tool. Interested users can download the XperiaFirm tool from XDA
Manually Install Android 8.0 Oreo Update on Xperia X/X Compact
Disclaimer: Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. Inexperienced users should not proceed with below steps.
1. Download Android 8.0 Oreo firmware file, build 34.4.A.0.364 (FTF) for Xperia X from here and for Xperia X Compact from here.
2. Download latest version of Sony firmware Flashtool [HERE] and install it on your PC. It will create a folder named Flashtool in your C drive.
3. Enable USB Debugging option on your Xperia phone (Settings > Developer Options > USB debugging)
4. Copy the downloaded FTF file to the folder “Firmware” inside the Flashtool folder
5. Now, run the Flashtool, select the FTF file and press OK.
Important: If you do not want to delete user data, just uncheck flashing userdata.sin file (we do not recommend it, as it may create additional issues)
6. Turn off your phone and when Flashtool prompted to connect your device, connect your phone to the PC by pressing Volume Down button on the phone. This will connect the phone in flashmode.
7. Wait for until the update installs and then reboot your phone.
You have now successfully flashed Android 8.0 Oreo firmware on your Xperia device. Enjoy! (Source – 1, 2)