Cydia should be on your home screen as usually a brown icon. It should be included with the jailbreak or you're not jailbroken correctly as you won't be able to add special programs without it.

Thanks @lorna, do you plan on posting here when the 6s version is ready for primetime? Thanks!

thanks @RockyMM, which iOS version are you running now?

I removed the Cydia tweak FastLoading which refreshes UI cache, and is known to make icons disapear. This has fixed the issue.

I created an account for the sole purpose of supporting this idea vocally. I plan to get one soon and I already fear how drastically different the brightness on it will be compared to my iPhone that has f.lux.

Thanks for your note - that's a tough area to be on a solar schedule -as we move the other versions to a circadian schedule that will help you a lot I think.

Just saw that it was added to the beta repo, thanks!

but, theres nothing in the settings app to adjust settings, what happened?

rebooted and its in the settings app, all is well!

Open f.lux settings, hold the CTRL key, and slide one back (one of them is locked but holding control, I think night can be made higher than day).

Pull day all the way down, hold CTRL, pull night up to your preference.

Hello Lorna, I startet my Iphone this morning again (what I tried already) and cydia made an update (what I also tried, but not worked) and now everything is all right. Thanks for your time and effort!

You are great!

Julian