In unicorn master (git), it seems kgio was removed (or unicorn no longer depends on it), so Ruby 4 may work there. But there is no RubyGems release that includes this change.
I can run unicorn from git, but it needs extra “release-time” build steps (generate lib/unicorn/version.rb, build/install ext/unicorn_http with ragel, and copy unicorn_http.so).
Workaround PR (exact steps): https://github.com/catatsuy/private-isu/pull/853 My mail to unicorn-public (may be inactive): https://yhbt.net/unicorn-public/20251227071714.D9328160070@mail.catatsuy.org/T/#u
Question: What is the best way to contact the unicorn maintainer, or request a RubyGems release?
2. Click on the homepage link in the lower right of the page.
3. Click the README and scroll down to Contact section. Or look at the ISSUES file: