Here's how to enable grayscale mode on Android 5.x or better:

1. Go to Settings.
2. Go to About Phone.
3. Find the Build Number.
4. Keep tapping Build Number until the phone acknowledges you as a developer.
5. Back out to main Settings screen.
6. Go to Developer Options.
7. Find and tap Simulate Color Space.
8. Select "monochromacy" from list.

That's all it takes to set your #android #smartphone to #grayscale mode.