And decent battery life, and a user-swappable battery, and good reception, and an SD card slot, and a decent camera, and a headphone jack, and a good UI, and a reasonable price, and sized to fit in just about any pocket.

I miss that phone.

Yeah, I have two, and there is no way to put some proper OS on them :~((.

I don't know if it's still maintained, but I used to build this one from source:

https://legacyxperia.github.io/

If you're curious about the possibilities, it might be worth searching xdaforums for "mango", and browsing threads like this one:

https://xdaforums.com/t/is-an-xperia-mini-still-usable-in-20...

I haven't bothered, mainly because 3G service is disappearing nowadays.

Will, check it out, thx.