2.2.0

I reworked the way brightness offset works, to give you more flexibility.

• If you have more than one external monitor, there is now a separate offset slider for each monitor in the menu.
• The app now allows you to make changes to your external monitors' brightness using all the system controls you can normally use. Any change you make will be saved as the offset for that monitor. The app will continue syncing brightness changes of your built-in monitor to your external monitor, while keeping the offset intact.

An example assuming your built-in display is configured as your primary display and you have one external UltraFine:

• You can change the brightness of both displays at once by, for example:
  • Using the Touch Bar slider for your built-in display.
  • Pressing the brightness keys on a keyboard.
  • Quickly swiping over the brightness icon on your Touch Bar if it's in your Control Strip.
• You can change the offset of your UltraFine by, for example:
  • Using the Touch Bar slider for your UltraFine display.
  • Holding Control and pressing the brightness keys on a keyboard.
  • Holding Control and quickly swiping over the brightness icon on your Touch Bar if it's in your Control Strip.
  • Using the slider in the menu of this app.

Note:
By default this functionality is disabled and the offset is "locked". This is because in some situations the offset might change without user intervention, like during display reconfiguration or waking from sleep. I've tried to prevent this as much as I could, but it still seems to happen once in a while. For users that rarely want to change the offset, this keeps the offset always the same like before. To enable the additional offset control, disable the offset lock in the menu.