The description of nineteen [substratum]
• Theme works best with custom 7.1.x/ 8.x ROMs with OMS support
• Theme also works with Google stock 7.1.x/8.x ROMs (note that stock ROMs have some theming limitation)
• LineageOS aren't fully supported
• OxygenOS aren't supported
• Doesn't work on Samsung devices running stock firmware
• You need substratum app from the Play Store to apply the theme
• You need to be rooted
IMPORTANT! When you open the theme in substratum app you'll see the drop down menu on top of the overlays. You need to choose one depending of your ROM Android version. There are also some overlays with different variant for specific Android version.
HOW TO apply theme on stock 8.1 ROM. When you installing overlays for the first time, after Building & Enabling you need to reboot and then Enabling overlays again. For updating an overlay you need to Disable it first and then Build & Enable, there's no need to reboot again, except for Android System overlay.
NOTE: AOSP apps like Clock, Messaging, Gallery, Contacts and Dialer may or may not work, because every custom ROM has their own variant of those apps, so if you get an error while compiling, just don't install them. I recommend installing those apps from the Play Store.
After every update I recommend clean install (uninstall all the overlays from the previous version, and then install the new ones). Also, after updating an app from the Play Store if it force close, try first to uninstall overlay for that app and install it again.
Don't report bugs if you're using custom DPI