Just added Ruby 4.0.0 to the ruby-versions database. ruby-install users can now safely install Ruby 4.0.0.
$ ruby-install -U ruby-4.0.0
Merry Christmas!
https://www.ruby-lang.org/en/news/2025/12/25/ruby-4-0-0-released/
https://github.com/postmodern/ruby-install#readme