**IMPORTANT** If your phone is not rooted, you need to manually grant the WRITE_SECURE_SETTINGS permission to the app. Detailed instructions on how to do so are provided within the app and in this video https://youtu.be/Rf3WndFgftI Gray-Switch allows you to conveniently switch your device's display mode between full color and grayscale either using a quick settings tile (Android 7 or newer), a launcher icon, automatically when the battery charge has fallen below a configured value, and/or durin