[niilohlin]

I would say that (La)TeX is probably the closest thing to "finished" software that I use on somewhat regular basis.

> A work is never completed, but merely abandoned.

[codesections]

LaTeX appears to be under active development. Its most recent release was just over two weeks ago: https://www.latex-project.org/news/

[JadeNB]

Yeah, better to say that TeX is (nearly) finished, with LaTeX still a roiling mass atop it.

[tmearnest]

Fun fact: when Knuth dies, TeX’s version number will converge to pi exactly.