Asus has officially announced that the Android 9.0 Pie will start rolling out to ZenFone 5 series handsets from January 2019 but it appears that a version of the ROM is already available for manual download direct from Asus. Tudocellular discovered the Android Pie ROM for the ZenFone 5 on Asus's servers and managed to take it for a test drive.
The ROM looks as if it was meant for the Brazilian market but Tudocellular reports that it should work on any international variant. Since the update is not yet available over the air, it requires manual download and installation. The publication notes that while there are no drastic changes to the overall user experience from the current version, ZenUI on Android Pie feels more snappier and intuitive.
As detailed in our hands-on review of the ZenFone 5Z, Asus already introduced a gesture-based navigation for ZenUI on Android 8.0 Oreo in a recent update. In Android Pie, gesture-based navigation looks to be more refined and presents a horizontal scrolling interface using a home bar just like the new Pixel and OnePlus phones. Of course, one can always go back to the button-based navigation system if needed.
Asus also introduces a new dark theme with this update via the Themes app. We get to see a more system-wide dark theme coverage compared to earlier implementations. We also get to see Android Pie's new volume controls.
The link to download the update manually can be found here and is just over 1 GB in size in compressed form. Remember that this ROM is only for the ZenFone 5 ZE620KL variant. After downloading, the zip file needs to be transferred onto a microSD card and installed via Recovery. Tudocellular does note that the update still has a few bugs. They are not show-stopping per se but it is recommended that users wait for the official FOTA update just to be on the safe side.
Source(s)
XDA Developers via Tudocellular (Portuguese)