This new macOS upgrade also includes smoke cloud wallpaper that was previously exclusive to iMac Pro. In macOS High Sierra 10.13.4, when users open a 32-bit application, they will be prompted to stop support in the future.
In the future, Apple plans to stop supporting 32-bit applications, just as iOS has stopped supporting 32-bit applications. Apple also mentioned that macOS High Sierra will be the last macOS system that can support 32-bit applications.