RISC OS: 35-year-old original Arm operating system is alive and well

> The only other OS that The Reg FOSS desk can think of from this era that's still around, actively maintained, and runs on modern hardware is NeXTstep – or, as Apple calls it today, macOS

If we're going to call macOS a current version of NeXTSTEP, then certainly Z/OS is a current version of OS/390, IBM i is a current version of OS/400, the BSDs (and indeed NeXtSTEP/macOS) are current versions of BSD Unix, Solaris is a current version of SunOS, and FreeDOS is a current implementation (if not a direct descendant) of DOS.

And I think it's fair to call Windows 11 a current version of Windows (if somewhat different from the DOS-based Windows versions of the 1980s.) ;-)

QNX also seems to be alive and kicking, as is Minix.

What are some other operating systems used in the 1980s that are actively maintained and running natively on recent hardware?

Alternately... is there any truly new OS from the 2000s or later that is widely used, or are we still stuck in the past with the likes of Linux, macOS, Windows, etc.? Even new-ish platforms like Java and the web seem to date back to the 1990s.