Android Oreo may soon get support for custom themes without rooting14
Developers tinkering with the developer releases of Android Oreo have found evidence suggesting that Google may finally be willing to implement a powerful theming engine in stock Android, and now we have further evidence in support for this.
The developers over at XDA found a way to take advantage of OMS (Overlay Manager Service) that is now integrated into Android 8.0, and to get Substratum themes up and running on it without any need for rooting or otherwise tinkering too much with the OS.
The method currently involves escalating permissions through ADB, with the only real drawback being that these permissions are lost after reboot, which means you'd either have to stick to the theme you've applied or punch in some ADB commands again.
The folks over at XDA are expecting the team behind Substratum to have some sort of theme manager app for Android Oreo in a week or so, so keep your eyes open for that. The app will be available for the Google Pixel/XL, the Nexus 5X, and the Nexus 6P, with the only prerequisite being that the device is running Android O.