HTC starts rolling out Android 8.0 Oreo stable (build 2.31.709.1) update for HTC U11 with a number of new features, enhancements, bug fixes and November 2017 Google security patches. The OTA (over-the-air) update weighs around 1.3GB and all HTC U11 units will get the update in the coming days. You can also download and install the update manually.
HTC U11 is one of the first non-Google devices to get official Android 8.0 Oreo stable update. Recently, Sony rolled out a stable Android 8.0 Oreo for its Xperia XZ Premium G8141 variant. HTC U11 stable Oreo update (build 2.31.709.1) is currently available in its homeland Taiwan. For global HTC U11 units, the Oreo 8.0 stable update is imminent.
Android 8.0 Oreo update will bring features like Picture-in-picture, Autofill, notification dots, multi-display, notification channels, better battery life, etc. alongside November 2017 security patches and Vo-WiFi enabled for users on Chunghwa Telecom carrier.
If you have not received the Oreo 8.0 update OTA notification for software version 2.31.709.1 on your HTC U11, then check it from the Home screen tap All apps > Settings > About > Software updates > Check now > Download. If update found, download it and once the download is complete, tap the System update to begin the upgrade process. After updating, your device will reboot.
If you have issue updating your HTC U11 via OTA (if for example out of WiFi coverage area and unable to download the OTA update), you can download the stock HTC RUU firmware file and sideload the update manually via HTC Sync Manager.
Note: For manual installation, you need to download the massive HTC Sense firmware file (RUU.exe) (around 1.3GB) to your PC and install HTC Sync Manager on your PC.
How to Install Firmware update on HTC U11 manually
1. Download HTC U11 Android 8.0 Oreo RUU.exe update file to your PC (coming soon).
2. After downloading the firmware, follow this detailed instruction to update your device manually to new software version.
OTA update method:
1. Download HTC U11 Oreo OTA update file (1.28.709.33 to 2.31.709.1) from here and save it on your phone.
2. Enable USB debugging on your phone, then boot your phone into Download mode (use Power button & Volume down button). In download mode, select ‘Reboot to bootloader’ option (use Vol key and Power button) and then select Reboot to Recovery.
3. In Recovery, select Apply update from phone storage, choose your OTA package and then press the Power button to flash the file.
4. After installation, your device will reboot automatically. (Source)