What's new with f.lux

beta version 4.134 (Feb 2024)

  • Windows 11 additional monitor fix, which is related to a bug with disabling on multiple monitors (also fixed)
  • Disabled “software mouse” cursor for Windows 11 insider

version 4.131 (Jan 2024)

  • Windows 11 monitor color reader fix
  • Avoid some operations that caused registry writes
  • Fixes for Hue and LAN API

version 4.130 (Sep 2023)

  • Additional fixes for Hue backoff integration (fixed a race condition at power on)
  • Workaround for some Fresco Logic adapters
  • Fixed map scaling
  • Not using Google Maps anymore for location preview, now using NASA’s “Black Marble” to show the earth at night

version 4.124 (June 2023)

  • Fixes for flashing
  • Updates to LAN API for programmable lights
  • Version data for WinGet users
  • Warning on Darkroom use with Intel Iris Xe (not compatible)
  • Stability and bugfixes
  • 30-minute backoff for manual adjustments to Philips Hue (beta)
  • Fix for invalid monitor chroma info

version 4.120 (June 2021)

  • Fixes for “red pixels” (overflow artifacts) on Intel Xe
  • Updated Philips Hue endpoint for better bridge discovery
  • Color profile safety checks (excluded large gamma values in ICC/ICM VCGT “formula” profiles to avoid washed-out screens)

version 4.118 and 4.119 (Feb 2021)

  • Try this: “Effects…” “Use Dark mode at sunset” to turn Windows Dark mode on at night and off during the day
  • DST smoothing (cues to make the time change easier)
  • Fixes for Hue reliability
  • Solar time
  • Fixes and performance improvements for Windows 10 May 2020 (build 2004)
  • Feb 2021:
  • Fixes a rare problem with X-Rite calibration files
  • Fixes a crash with Yeelight

Solar Time?

Solar Time is the time a clock would say if it were based on the sun. If our clocks worked like this, noon would happen when the sun was at its highest point each day.

We now show Solar Time in f.lux interface, because we think it’s important.

If your solar time is after the current clock time, it’s likely that you live in a place that’s easy for night owls to be (because they can wake up late). And if you’re in a place where the solar time is much earlier than what your clock says, it’s easier for early birds, because they can go to bed early.

version 4.111 (Aug 2019)

  • Update for compatibility with latest Windows 10
  • Works around multiple monitor issues and per-monitor disable
  • Improves support for DisplayLink (docking stations and USB-connected displays) and older GPUs. Full support for devices that support “gamma ramp” via the registry.
  • Fixes some crashes

version 4.104 (May 2019)

  • We are seeing a memory leak from a bug in the latest version of Windows 10 (18362). This build slows down the leak, and for now, we’ve made f.lux restart (quietly) when RAM usage gets too high. Hopefully this will be fixed soon.
  • The “surface keys” menu item is visible again in options
  • Fixed a problem with fullscreen disable

version 4.100: Disable per monitor (Apr 2019)

  • Adds per-monitor disable for people with TVs and e-Paper displays
  • Fixes a Philips Hue brightness problem
  • Fixes a problem that broke Darkroom below 1900K
  • Adds option to turn off GPU usage below 1900K (off for Windows 7)
  • Fixes maps “search” button
  • Defers to corporate installs on same machine
  • Handles unicode menus better
  • Makes disable until morning wait until after sunrise
  • Fixes a file handle leak
  • Fixes for Windows Insider (18351+)

version 4.84: Grayscale mode, distraction-free reading

November 2018

This new version of f.lux has a grayscale mode and new key to turn it on: Windows + End.

You may already know about Tristan Harris and the Center for Humane Technology. They’ve explained how apps mess with our attention, so even the colors used on our screens are chosen to distract you. At first, we didn’t think this problem would be as bad on the desktop as it is on your phone.

The big surprise is how distracting the icons on the top and bottom of your screen are. These icon colors are the kind of thing you see in candy stores and on fire alarms, but we have to ignore them just to get work done. Without those colors, your computer looks more like a magazine that can help you focus on reading or thinking—it feels different, like a sheet of paper.

Also, turning your devices to grayscale does not remove blue light, so f.lux will continue to do what it does.

In this version, there’s also dusk-to-dawn support for people with Hue lights, so you can put Hue lights outside and use f.lux to turn them off during the day.

There are some bugfixes too.

Thanks for using f.lux. We hope you enjoy it.

If you’d like to report a bug, or issue a complaint (or a compliment), please visit our forum.

version 4.78

Sep 21 2018

  • Fixed bugs that caused sliders to draw wrong at 125% and 200%
  • Slightly slower dimming with Alt-PgDn
  • Windows 10 fixes
  • Installer fixes

June 19 2018

  • More flashing fixes
  • Disabled function-key hotkeys (you can turn them on again by hand)
  • One more update to fix a problem with DisplayLink

May 30 2018

  • Fixes a problem with the recent Windows 10 April update that resets f.lux’s color settings when devices are added to the system (including headphones and mice).
  • Fixes some crash bugs

April 2 2018

  • Adjust warmth of Hue lights (relative to screen)
  • Early support for LIFX via LAN API
  • Early support for YeeLight (Xiaomi Mi) via LAN API
  • Options menu reorganized (so there can be more)
  • Checkbox to allow a laptop to sleep even when lighting controller is on
  • Some installer and crash fixes

version 4.66

January 15 2018

  • Clicking the graph now shows you the “advanced” three-slider mode. A second click previews (like it used to).
  • New darkroom hotkey: Alt-Shift-End
  • Maps display uses a newer browser version for Google Maps compatibility
  • Starting f.lux from the start menu shows the app again
  • Multiple monitor disable now uses color profile
  • 0 latitude is now allowed
  • Adjusted long fade timing just a bit
  • Hue brightness is re-calibrated (somewhat brighter)
  • Disable for remote desktop now works faster
  • Stops showing app window on Alt+Shift+PgDn
  • More accurate “disable” timing
  • Options menu now reports more monitor info
  • Fixed a crash bug in the way we use Windows Location (thanks Microsoft app compatibility team)
  • Better crash reporting (it is optional to send)

version 4.55

Oct 12 2017

  • Several text changes to menus (explaining difference between “current colors” and “effects”)
  • Remote Desktop automatically disables (on remote side)
  • Avoids showing notifiers when f.lux is disabled
  • Fixes for location dialog (Windows 7 especially)
  • Help setting up your wake time, one time
  • About box links to fluxometer
  • “Classic f.lux” is now more like v3: simple graph, wake time features are disabled
  • Hue brightness fixes (when f.lux is disabled)
  • Windows Store apps can be disabled individually now
  • Options menu now can show your video card version (for debugging)
  • Many fixes for disable by app (now shows the full list so you can re-enable)
  • Notifier fixes: layout and text about color changes

version 4.47

Sep 15 2017

  • Time formatting fixes (for international users)
  • Fixes for location dialog box (sometimes zip codes were broken)
  • Prompts to unlock color range when f.lux starts
  • Fixes for mouse cursor when disabling fullscreen apps
  • Improvements to fast transitions and sunset timing

version 4.43

Aug 4 2017

  • Fixes fullscreen disable bug (sometimes would disable for desktop)

version 4.42

Aug 3 2017: If you want to receive beta builds in the future, please use the About box to opt in

  • Major fixes for Hue lights (White Ambiance)
  • Added About box with info, links and options
  • Made a close button for notifiers
  • Fixed a crash at exit
  • Fixed a sunset timing problem
  • Avoided using bad monitor data

version 4.41

July 27 2017

  • Stopped changing tray tooltips so much, to fix a bug on Windows 7

version 4.40

  • Fixed a problem with determining location
  • Added new eyestrain preset

version 4.39

  • Fixed a bug that made too many notifiers appears (only for some people)

version 4.38

  • New notifiers, so they don’t make tons of entries in Windows “notifications and actions” (and also they work better on Windows 7)

version 4.36-4.37

  • Can exclude specific Hue lights from f.lux schedule
  • Changing the way we show readmes on update, so not every version will pop a webpage (you’ll get a notifier instead)
  • Fixes for dimmed shadow boosting
  • Fixes for backwards alarm clock while you’re away from the computer

version 4.35

  • Fixed a case where f.lux fails to come back when monitor sleeps

version 4.34

  • Wakeup from sleep fixes
  • Fixes for northern latitudes
  • Workaround for a bug in 16215 (insider)
  • Lower CPU usage

version 4.33

  • Easier location finding
  • Some fixes for LAN-based lighting
  • Performance improvements

version 4.31 and 4.32

  • Disable for fullscreen apps (using this allows you to disable one monitor for movies)
  • Disable by app works for 64-bit apps again

version 4.30

  • Disable by app fade timing is improved
  • Cursor is set to hardware mode at exit
  • Minor text edits

version 4.29

  • “Disable by app” only notifies you once per session, not all the time
  • Actual app names are now shown for “disable by app”. (You may have to disable some apps again.)
  • Tray icon now stays hidden when you hide it
  • Some menu text changes

version 4.28

Menus and oopses:

  • Menus are juggled around to help simplify the UI (we are not done yet)
  • Mouse cursor checkbox was broken, now fixed

version 4.26

Some fixes:

  • Software mouse cursor now switches on automatically when colors change, so you keep a hardware cursor during the day (you’ll have to turn it on again in Options)
  • When you don’t enter your location, defaults are quite a bit better
  • Fixes some cases for wake from sleep
  • Some adjustments to vignette mode

version 4.25

This version tries to improve color calibration and fixes some bugs. What’s new:

  • We noticed a lot of laptops are looking very “green-yellow” so we spent some time to figure out what was going on. We were able to pull some data out of the monitors that describe their colors better than Windows does, and so we’re trying to use that data to do more accurate colors now. In the Options menu, there is a checkbox called “Use Monitor Data for Calibration”. We’re turning this on for everyone in this build, so we’d like to know if you think it looks better, or worse!

  • Second, we’ve improved “crushed shadows” by adjusting the response automatically when you dim your screen, so we think photos look a lot better in this new build

  • There’s a new full-screen vignette mode we’re trying out, which manages to show about 60% less light, while still being readable (for some things).

  • Enabling software mouse cursor doesn’t require a logout anymore

  • Bugs fixed on wake from sleep. f.lux should always come back now.

  • Notifiers should never steal keyboard focus, and hotkeys are usable in fullscreen apps/games, because we don’t pop notifiers that kick you back to the desktop

version 4.21 (a model of you)

We added a lot to this update, so we need your feedback.

In this version, we’re showing everyone a little bit of the way we think about f.lux, giving you some measurements that we think are important. So far, we’ve not really brought “you” and your circadian timing into the f.lux interface.

How light affects you

In this new build, we’ve exposed one of our models of how the light from screens affects your body (based on your screens’ sizes, and using our 5,000-person survey to approximate your viewing distance).

As you adjust settings in f.lux now (or even as you change your laptop’s backlight, which is important), you’ll see one of five common-sense scores for how much light you’re seeing:

Circadian darkness

  • Bright as Day
  • Ready to Work
  • Staying up Later
  • Winding Down
  • Circadian Darkness

As well, you’ll see a percentage, which we call “% daylight”. It’s a score for how much circadian effect the light you’re seeing might have, compared to broad daylight.

But it’s also important to say, everyone’s a little bit different, so this is just a guideline. You might be more sensitive (especially if you’re under 20) or less sensitive (if you’re over 50, or if you spend a lot of time outdoors).

Is light making you earlier or later? It’s about time too.

Light you see in the morning makes your internal clock “advance” or set itself earlier, and light you see at night makes your clock “delay”. When these adjustments cancel out, your clock stays in about the same place. When you see too much light at night, your clock delays and you want to stay up later.

This new f.lux version indicates the times of day that light is likely to make you later or earlier, so if you open the Preferences screen at night you will see “Light is making you later” and correspondingly “Light is making you earlier” in the morning.

Other changes and fixes in this update

  • Notifications are redesigned, when you use the hotkeys (alt-pgup, alt-end, etc)
  • Some extra support for wide color ranges on Windows 7
  • Gaming mode (safe mode) is removed, because we’ve incorporated everything it does, finally. Use “very fast” transitions if you notice problems
  • We now ask for the “earliest” time you wake up, to clarify what you should do when you have a variable schedule

v4 beta features


  • Bedtime mode: warmer mode gets you ready for sleep
  • Backwards alarm clock: reminder not to stay up late
  • Presets to help adjust your settings
  • Color filters for eyestrain and other uses
  • Wider range of color settings
  • New hotkeys to adjust color (alt+shift+PgUp and alt+shift+PgDn)


  • Reduced impact on game framerates
  • Resolution independent interface, for high DPI
  • DisplayLink works in a lot more cases now

Smart Lighting:

  • Hue integration now supports more light types
  • LAN API with support for telling other devices when f.lux changes

More release notes (bugs and updates)


  • Optimized background performance more (should improve framerate drops), fixed some bugs
  • Added ability to toggle software cursor in the Options (prevent white cursors!) - requires a reboot or logout


  • Default to “slow transition” on purpose! We thought we had done that already, but people who had the old version were getting a fast transition.
  • If you don’t like this, change it in options


  • “Very fast” transition option added for slow GPUs
  • Make custom filters show status when selected
  • Make modes (filters, darkroom) cancel when sliders are moved
  • Disable by app fixes


  • Make wake time work on restart


Dec 5 2016

This build fixes a number of minor issues with Windows 10 Anniversary Edition:

  • DisplayLink USB monitors no longer cause flashing on the main display
  • Our “NSIS” installer software has been updated due to a security vulnerability
  • Code signing now uses SHA256 to increase security

3.10 bugfixes

Oct 23 2013

This build fixes a number of problems encountered with 3.9:

  • Some users with high-end monitors and video cards experienced persistent flashing. This build fixes most of these bugs. (If you see flashing a few times right after login, we’re still working on it.)
  • f.lux now shows the location dialog when you haven’t set your location and reboot (rather than showing the main window, which confused many people.)
  • Fixes for Philips Hue
  • Clarified text in several places based on user feedback (restarting, asking for location)


Oct 15 2013

This build is going live as our main build, a big update from 2.0.

Copyright f.lux Software LLC 2008-2020