Asus has started pushing out a new update to its ZenFone 4 (ZE554KL) smartphone. Arriving as version V15.0405.1711.76, it's a major update that brings along Android 8.0 Oreo (which is inline with what was promised).
The change-log published by the company includes features like more friendly setting UI design, background limits, autofill, smart text selection, and picture-in-picture. So as you can see, all the Oreo goodies are included in the update.
Given the fact that it's an OTA roll out, it might take time for the update to hit your device - Asus says it'll take about one week for the system to complete the autopush.