ASUS has started rolling out the Android Pie 9.0 update for it’s Last Year Flagship the Zenfone 5Z. The update is rolled out for India today. Few Countries have already received the update. ASUS has rolled out the update as Promised during the Launch.
ZenFone 5Z (ZS620KL)
Since the server pushes update notice to different serial numbers by batches, it may take some days for you to receive the FOTA notice. Thanks for your patience. You may tap “System updates” in[Settings] >[System] to check if there is new firmware available. Or, you can also try to manually update firmware by referring to the following link.
How to update firmware on my phone?
Android P upgrade
Update security patch