To be honest, while KolibriOS is open-source, I wouldn't call it "active" that much. MenuetOS has progressed much further than KolibriOS over the years in both performance (it has SMP support!) and being 64-bit.

You can check the commit activity: https://git.kolibrios.org/KolibriOS/kolibrios/commits/branch... - last commit on the first page is already 10 months ago.

And compare it to "News" on the MenuetOS page: - 22.01.2026 M64 1.58.10 released - Improvements, bugfixes, additions

- 26.08.2024 M64 1.53.60 released - MPlayer included to disk image

- 24.07.2024 M64 1.52.00 released - Partial Linux layer (X-Window/Posix/Elf)

- 12.07.2024 M64 1.51.50 released - New graphics designs by Yamen Nasr

- 08.05.2024 M64 1.50.80 released - Fasm-G, many 32 bit apps & sources

last commit was a week ago https://git.kolibrios.org/KolibriOS/kolibrios/commit/dd9a7b9...