A work around I've found is another "last chance" to update to Windows 10.

Windows 10 - Assistive Tech Upgrade

This is a lot like using a sledgehammer to hang a picture but its all I could find. Thanks anyway herf! Keep up the good work.

DisplayLink, it's not for everyone...

@herf With the recent update, my f.lux started to not work through to the monitors on my docking station. I followed your steps and it now works perfectly! Thank you!

Forgot to mention that the old laptop was attached to these same two monitors through the Dell docking station, and both monitors dimmed as expected with f.lux. Also, when connected to the dock, the laptop is generally closed, so the laptop monitor is turned off, and the Dell monitor (Monitor #1) is the main screen. Uninstalled and reinstalled f.lux, and expanded the color range again. Still doesn't work.

I noticed this came out yesterday. Looks like DisplayLink is working on supporting f.lux. Windows only. http://www.displaylink.org/forum/showthread.php?p=82958#post82958