[yjftsjthsd-h]

Illumos is still actively developed, open source, and can trace its lineage back to actual unix.

For that matter, we've had new members joining the family over the years; https://www.redox-os.org/ is, in their own words, "a complete Unix-like microkernel-based operating system written in Rust, with a focus on security, reliability and safety."

[johnisgood]

For anyone wondering, OpenSolaris -> illumos (e.g. OpenIndiana). Good times!

[nineteen999]

Not to mention that Version 4 UNIX source code was just released!

[yjftsjthsd-h]

Well, yes, but that's not exactly a modern OS, just historically interesting.