Jolla Pushes Out Sailfish OS 2.1.4 Into Early Access

[DrYak]

Are there any budget smartphones that will allow me to install Sailfish OS as a holdover for when Purism releases Librem 5 by early 2019?

As others have mentioned, you can find Sony Xperia X at discounted prices, now that it's not Sony's Flagship anymore.
It's not a *budget* phone per se, but it's something that you're going to find more discounted in the future, as vendors will look to put more recent Sony Xperia phones on the shelves.

(And given how Sailfish OS is lightweight, it's still a very responsive phone).

I downgraded my Android smartphone from Oreo to Nougat because night mode is exclusive to Pixel smartphones {...} Anyway, does Sailfish have a night mode feature similar to GNOME?

I can't manage to find information about Night mode. Is that some screen backlight auto setting for when using in a dark room/setting ?
(Sailfish handles some automatic light detection and screen brightness adjustments
There information in forums and 3rd party patches/utils about how to tweak it.
Out of the box I find the brightness a bit erratic)

and I do not like the new quick settings in Oreo. Plus, I get double notification sound from Twitter in Oreo versus one in Nougat.

Keep in mind that although Sony *is* encouraging experimenting with 3rd party OSes on their Xperia devices (there's this open device program they're having) so it's definitely not an unofficial OS - Jolla and Sony are collaborating a bit on this one - BUT it's still very early versions.
They're bound to be a few hiccups, so if you don't like Oreo because not everything is perfect, then I wouldn't recommend counting on either Sailfish X for now, nor on Purism's Librem 5 during its first year or so.

(Though I can't vouch for this early release version 2.1.4 - I'm waiting for the final public release before updating my Xperia and keeping on 2.1.3 for now).

but as I want control over my smartphone and tinker what's in it, I'll be waiting for Librem 5 which I can have GNOME in my smartphone I want freedom and whatever changes Google makes to Android that I'm not satisfied, I could care less about buying new smartphone that would come with Android 9.0 or later,

I totally understand the "I want control". It's the reason for my preference toward GNU/Linux running phones.

Fairphone is exclusive to Europe and I'm in the US.

Hopefully, one day, cell phone radio standards will converge to the point where phone work world-wide with full features.

Xperia X at less than $300 in Amazon is small at 5", as I want more real-estate for reading web pages (Firefox) and viewing restaurant menus using the camera.

You mean using your smartphone as an electronic magnifier/reading glasses ?

[GraysonPeddie]

Twilight changes the color temperature by removing the blue component of the screen depending in the intensity (where low intensity removes a bit of blue while full intensity removes blue completely, making it look yellow or red depending in color temperature). Dimming a screen does not remove the blue component of the screen. Ever tried Night mode in GNOME 3.26+ and Night mode in Windows 10?

And yes, I use my smartphone as an electronic magnifier. There are Android apps out there that can do that, although most of the apps contain ads. There are magnifying apps that can let you turn on the LED light. This makes it very useful if I don't carry a separate magnifier, as I'd like to have a 5.5"+ screen. Even better, 6" at 16:9, but most people don't like carrying large phablets for one-handed operation. I do not have sources to back up my claim, as there are not that many smartphones that have 6"+ with a 16:9 display. Sure, there are 6" 18:9 phones out there, but height in landscape mode is more important to me and width in portrait mode. I could settle for 5.5" screen for Purism Librem 5, though.

[Nille_kungen]

I can't manage to find information about Night mode. Is that some screen backlight auto setting for when using in a dark room/setting ?

If you ever used an dedicated GPS in your car, the ones that was very common before the smartphones, then you also know that when the night came it changed theme an everything was dark no mater what you did or what application you used then you know what the "new" night mode is.
It's not something new and personally i like to use dark themes all the time like the Nokia N9 had by default and it also saves battery.
Some night modes only makes the screen a little darker like if you lower the brightness on your laptop.

[DrYak]

Okay, thanks for the explanation (yup, I see what you mean by stand alone GPS' night mode)

Under Sailfish, as mentioned by others above, you have "ambiances" which let you theme you phone. Each ambience can have it's own set of settings, sound theme, etc. in addition to background picture.

Lots of people use Situations which let you write rules and change settings (including ambiences) based on them. You could switch easily between a day and night ambience based on a clock, but currently there's no way to easily detect a dark room. you'd have to detect "indoor" condition indirectly (e.g.: GPS position, visible Wifi networks, Cell towers, etc.)

Given that the Xperia X screen is an IPS LCD, a theme won't change the power use much except by lowering the screen brightness.
(unlike OLED screens, there's no big difference between white and dark pixels on small-sized LCD).