2.4.0-beta.1

Support for Apple Silicon Macs.

This version uses a different private framework to get/set brightness and is not as well tested as version 2.3.2.
Intel Mac users might want to continue using 2.3.2 for now.

2.3.2

Celebrating the new year and 100 Github stars with this very important release.

• Updated menu bar icon to better match system icons in Big Sur.

Before:

After:

Still not great, but better at least.

2.3.1

Improved display detection, 2.3.0 still had issues.

2.3.0

• Fix display detection on Big Sur.
• A 2nd gen UltraFine can now be used as a source to sync brightness to a 1st gen UltraFine.

2.3.0-beta.2

• Support syncing from 2nd generation 4k UltraFine to other displays (beta.1 could only detect 2nd gen 5k model).
• Started syncing to connected 2nd gen UltraFines again. Seems like most people like to rely on this app instead of the built-in ambient light sensor of the UltraFine.

To summarize:
If a built-in display is detected, the app will sync from the built-in display to all connected 1st and 2nd gen UltraFine displays.
If no built-in display is detected, the app will sync from the first 2nd gen UltraFine it finds to the other 1st and 2nd gen UltraFine displays.

2.3.0-beta.1

Rough initial support for mixed 1st generation and 2nd generation UltraFine setups.
If no built-in display is found, the app will now use the first 2nd gen UltraFine it finds as a source. (#17)
It will no longer try to sync to a 2nd gen UltraFine (as they support auto brightness).

This for now only takes into account the 5k UltraFine model, because I use the model number to distinguish and I don't know 4k UltraFine model numbers.
If you have a 2nd gen 4k UltraFine, you could help by providing the model number Brightness Sync reports by opening the menu in the menu bar and pressing ⌘C to copy some diagnostics about your connected displays to your clipboard (the menu will close).

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.

2.2.0-beta.3

Small update.

• Some internal changes to UltraFine detection
• Exposed polling interval as user default (#15)

2.2.0-beta.2

• Fix offsets changing when switching users
• Fix offsets changing when connecting/disconnecting monitors

2.2.0-beta.1 - Control offset with your keyboard!

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.

I'm releasing this as a beta version since I'm not sure how many people even want this feature and the old version is pretty tried and tested by now.