According to the release notes, the OTA update adds support for PUBG HD graphics. In case you missed it, the company made a mess of it in the Android Pie Update, but has patched the issue now.
Navigation Pill icon bug fixed in Max Pro M1 May 2019 Update
If you read our Zenfone Max Pro M1 Android Pie Update Review, you may have noticed that one of the criticisms was regarding the Navigation Pill icon. This option is not enabled by default, but if you toggled gestures on, you may encounter the bug. Basically, a circle from the regular nav bar appears behind the pill icon which makes it look really weird.
The company never acknowledged the bug, but it has been quietly fixed in the Max Pro M1 May 2019 Update.
We tested the Google Camera app, and yes the Camera2API is still enabled in the latest update. HD Audio support however, isn’t back yet.
The build number of the Max Pro M1 May 2019 Update is 16.2019.1905.053-20190513. The OTA update from the previous version weighs about 400MB in size. The full image for the WW-16.2017.1905.053 version weighs 1.53GB and can be downloaded from the official website.
You can manually check for the update by navigating to the Settings > System > Advanced > System Updates.