The update which is already rolling out as an OTA in India fixes the screen flickering problem that occurs when you start or stop video recording. It has also improved the quality of video calls and the focus speed of the camera when recording a video.
There are also improvements for the notification LED, NFC, and secure album. The release note also mentions a security patch (June 5).
If you already have the Zenfone 5Z, check for the update under System Updates. You can also manually download it on to your device from here. Copy the file to the root folder of your device and you should get a notification to install the update.
The Zenfone 5Z rocks a 6.2-inch 2246 x 1080 display with an 18.7:9 aspect ratio. Thre is a Snapdragon 845 processor under the hood paired with 4GB/6GB/8GB of RAM and 64GB/128GB/256GB of storage.
It also has dual 12MP rear cameras, an 8MP front-facing camera, a fingerprint scanner, and dual SIM slots. It runs Android 8.0 Oreo and has a 3300mAh battery with Quick Charge 3.0 support.