ASUS has announced that has rolled out the Android 9.0 Pie update for the ZenFone 5 (ZE620KL).
The update, released on January 2, 2019, with version number V16.0610.1812.58, will bring improvements and features that come with Android 9.0 Pie, as well as security patches and tweaks on the ZenUI.
The update will be pushed via OTA so users might receive a notification to download. Alternatively, you can also check by going to Settings –> System –> System Updates.
source: ZenTalk