Iris

I just installed the free Iris Mini in macOS 13 on M1 hardware. Not updated since 2018, so is Intel only and I'm not sure how well it might work compared to the native macOS control. It is said to be able to "reduce the screen brightness without increasing the flicker rate of the monitor". Can it really do that without knowing about current Apple hardware? And this is not what the native function does? I'll see what I think.

Wrong version listed.
The downloaded file is v0.9.2.5.

And the new version ROYALLY SUCKS!

There's no fully-functional trial period, it's crippleware.

Don't download unless you intend to pay for it, because all the settings are locked: "You need Iris Pro to access this section."

You're not allowed to adjust the brightness or temperature anymore.
You can't even set your location so it knows when to change.

And when you close the Settings window (since it's useless anyway), the app QUITS!

Either use it with the one setting provided, or BUY IT!

Although it has its own issues, I recommend f.lux over this POS.

macOS 10.12 Sierra provides the evening blue reduction feature for compatible displays. For other displays try: A) f.lux: The original, entirely free app for this purpose: https://www.macupdate.com/app/mac/37261/f-lux B) Iris: The free version is generally the same as f.lux. I personally do not like the sales pitch for Iris specifically because it attempts to pretend it provides "safety." There is literally no 'safety' provided. I'm saying this as an expert of color and light technology. Having said that, many people are sensitive to the blue light emissions of various computer displays, which may cause their body to have difficulty falling asleep at night, Shifting the display color balance toward red at night is the purpose of macOS, f.lux and Iris. There are also some displays (none by Apple I am aware of) that can cause flicker. If you have such a display, Iris may reduce the resulting annoyance. Iris Pro provides added features built into the developer's 'Color-API'. Whether these features are useful will be up to the user to decide.

This program is listed as free but is actually 5-10 dollars depending on what features you wish to have.

I concur that it's great. Full disclosure, I encouraged the developer to get this on MacUpdate. It has many nice features. I think the UI could use some improvement, and I'd like to see hot keys available for the Mac. (They do work with Windows at the moment.) But the developer has been very responsive, appears to work on Iris regularly, and seems very open to suggestions. I believe Iris will continue to evolve. I've seen some reviews of program in MU that seem to like to bash another program with "Program X does this for free." That never seemed an appropriate manner for evaluating a program. One can always find free programs that do some of what another program does. That does not necessarily make any particular program bad. In this instance, Iris is most likely to be compared to f.lux, and I hope people don't bash Iris in terms of "f.lux is free." That is true; and f.lux is a very good program. I would encourage anyone to please check out Iris before making comparisons. Iris does what f.lux does, but it also does a number of other things as well.